diff options
Diffstat (limited to 'third_party/git/read-cache.c')
| -rw-r--r-- | third_party/git/read-cache.c | 3609 |
1 files changed, 3609 insertions, 0 deletions
diff --git a/third_party/git/read-cache.c b/third_party/git/read-cache.c new file mode 100644 index 000000000000..52ffa8a3139f --- /dev/null +++ b/third_party/git/read-cache.c @@ -0,0 +1,3609 @@ +/* + * GIT - The information manager from hell + * + * Copyright (C) Linus Torvalds, 2005 + */ +#include "cache.h" +#include "config.h" +#include "diff.h" +#include "diffcore.h" +#include "tempfile.h" +#include "lockfile.h" +#include "cache-tree.h" +#include "refs.h" +#include "dir.h" +#include "object-store.h" +#include "tree.h" +#include "commit.h" +#include "blob.h" +#include "resolve-undo.h" +#include "run-command.h" +#include "strbuf.h" +#include "varint.h" +#include "split-index.h" +#include "utf8.h" +#include "fsmonitor.h" +#include "thread-utils.h" +#include "progress.h" + +/* Mask for the name length in ce_flags in the on-disk index */ + +#define CE_NAMEMASK (0x0fff) + +/* Index extensions. + * + * The first letter should be 'A'..'Z' for extensions that are not + * necessary for a correct operation (i.e. optimization data). + * When new extensions are added that _needs_ to be understood in + * order to correctly interpret the index file, pick character that + * is outside the range, to cause the reader to abort. + */ + +#define CACHE_EXT(s) ( (s[0]<<24)|(s[1]<<16)|(s[2]<<8)|(s[3]) ) +#define CACHE_EXT_TREE 0x54524545 /* "TREE" */ +#define CACHE_EXT_RESOLVE_UNDO 0x52455543 /* "REUC" */ +#define CACHE_EXT_LINK 0x6c696e6b /* "link" */ +#define CACHE_EXT_UNTRACKED 0x554E5452 /* "UNTR" */ +#define CACHE_EXT_FSMONITOR 0x46534D4E /* "FSMN" */ +#define CACHE_EXT_ENDOFINDEXENTRIES 0x454F4945 /* "EOIE" */ +#define CACHE_EXT_INDEXENTRYOFFSETTABLE 0x49454F54 /* "IEOT" */ + +/* changes that can be kept in $GIT_DIR/index (basically all extensions) */ +#define EXTMASK (RESOLVE_UNDO_CHANGED | CACHE_TREE_CHANGED | \ + CE_ENTRY_ADDED | CE_ENTRY_REMOVED | CE_ENTRY_CHANGED | \ + SPLIT_INDEX_ORDERED | UNTRACKED_CHANGED | FSMONITOR_CHANGED) + + +/* + * This is an estimate of the pathname length in the index. We use + * this for V4 index files to guess the un-deltafied size of the index + * in memory because of pathname deltafication. This is not required + * for V2/V3 index formats because their pathnames are not compressed. + * If the initial amount of memory set aside is not sufficient, the + * mem pool will allocate extra memory. + */ +#define CACHE_ENTRY_PATH_LENGTH 80 + +static inline struct cache_entry *mem_pool__ce_alloc(struct mem_pool *mem_pool, size_t len) +{ + struct cache_entry *ce; + ce = mem_pool_alloc(mem_pool, cache_entry_size(len)); + ce->mem_pool_allocated = 1; + return ce; +} + +static inline struct cache_entry *mem_pool__ce_calloc(struct mem_pool *mem_pool, size_t len) +{ + struct cache_entry * ce; + ce = mem_pool_calloc(mem_pool, 1, cache_entry_size(len)); + ce->mem_pool_allocated = 1; + return ce; +} + +static struct mem_pool *find_mem_pool(struct index_state *istate) +{ + struct mem_pool **pool_ptr; + + if (istate->split_index && istate->split_index->base) + pool_ptr = &istate->split_index->base->ce_mem_pool; + else + pool_ptr = &istate->ce_mem_pool; + + if (!*pool_ptr) + mem_pool_init(pool_ptr, 0); + + return *pool_ptr; +} + +static const char *alternate_index_output; + +static void set_index_entry(struct index_state *istate, int nr, struct cache_entry *ce) +{ + istate->cache[nr] = ce; + add_name_hash(istate, ce); +} + +static void replace_index_entry(struct index_state *istate, int nr, struct cache_entry *ce) +{ + struct cache_entry *old = istate->cache[nr]; + + replace_index_entry_in_base(istate, old, ce); + remove_name_hash(istate, old); + discard_cache_entry(old); + ce->ce_flags &= ~CE_HASHED; + set_index_entry(istate, nr, ce); + ce->ce_flags |= CE_UPDATE_IN_BASE; + mark_fsmonitor_invalid(istate, ce); + istate->cache_changed |= CE_ENTRY_CHANGED; +} + +void rename_index_entry_at(struct index_state *istate, int nr, const char *new_name) +{ + struct cache_entry *old_entry = istate->cache[nr], *new_entry; + int namelen = strlen(new_name); + + new_entry = make_empty_cache_entry(istate, namelen); + copy_cache_entry(new_entry, old_entry); + new_entry->ce_flags &= ~CE_HASHED; + new_entry->ce_namelen = namelen; + new_entry->index = 0; + memcpy(new_entry->name, new_name, namelen + 1); + + cache_tree_invalidate_path(istate, old_entry->name); + untracked_cache_remove_from_index(istate, old_entry->name); + remove_index_entry_at(istate, nr); + add_index_entry(istate, new_entry, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE); +} + +void fill_stat_data(struct stat_data *sd, struct stat *st) +{ + sd->sd_ctime.sec = (unsigned int)st->st_ctime; + sd->sd_mtime.sec = (unsigned int)st->st_mtime; + sd->sd_ctime.nsec = ST_CTIME_NSEC(*st); + sd->sd_mtime.nsec = ST_MTIME_NSEC(*st); + sd->sd_dev = st->st_dev; + sd->sd_ino = st->st_ino; + sd->sd_uid = st->st_uid; + sd->sd_gid = st->st_gid; + sd->sd_size = st->st_size; +} + +int match_stat_data(const struct stat_data *sd, struct stat *st) +{ + int changed = 0; + + if (sd->sd_mtime.sec != (unsigned int)st->st_mtime) + changed |= MTIME_CHANGED; + if (trust_ctime && check_stat && + sd->sd_ctime.sec != (unsigned int)st->st_ctime) + changed |= CTIME_CHANGED; + +#ifdef USE_NSEC + if (check_stat && sd->sd_mtime.nsec != ST_MTIME_NSEC(*st)) + changed |= MTIME_CHANGED; + if (trust_ctime && check_stat && + sd->sd_ctime.nsec != ST_CTIME_NSEC(*st)) + changed |= CTIME_CHANGED; +#endif + + if (check_stat) { + if (sd->sd_uid != (unsigned int) st->st_uid || + sd->sd_gid != (unsigned int) st->st_gid) + changed |= OWNER_CHANGED; + if (sd->sd_ino != (unsigned int) st->st_ino) + changed |= INODE_CHANGED; + } + +#ifdef USE_STDEV + /* + * st_dev breaks on network filesystems where different + * clients will have different views of what "device" + * the filesystem is on + */ + if (check_stat && sd->sd_dev != (unsigned int) st->st_dev) + changed |= INODE_CHANGED; +#endif + + if (sd->sd_size != (unsigned int) st->st_size) + changed |= DATA_CHANGED; + + return changed; +} + +/* + * This only updates the "non-critical" parts of the directory + * cache, ie the parts that aren't tracked by GIT, and only used + * to validate the cache. + */ +void fill_stat_cache_info(struct index_state *istate, struct cache_entry *ce, struct stat *st) +{ + fill_stat_data(&ce->ce_stat_data, st); + + if (assume_unchanged) + ce->ce_flags |= CE_VALID; + + if (S_ISREG(st->st_mode)) { + ce_mark_uptodate(ce); + mark_fsmonitor_valid(istate, ce); + } +} + +static int ce_compare_data(struct index_state *istate, + const struct cache_entry *ce, + struct stat *st) +{ + int match = -1; + int fd = git_open_cloexec(ce->name, O_RDONLY); + + if (fd >= 0) { + struct object_id oid; + if (!index_fd(istate, &oid, fd, st, OBJ_BLOB, ce->name, 0)) + match = !oideq(&oid, &ce->oid); + /* index_fd() closed the file descriptor already */ + } + return match; +} + +static int ce_compare_link(const struct cache_entry *ce, size_t expected_size) +{ + int match = -1; + void *buffer; + unsigned long size; + enum object_type type; + struct strbuf sb = STRBUF_INIT; + + if (strbuf_readlink(&sb, ce->name, expected_size)) + return -1; + + buffer = read_object_file(&ce->oid, &type, &size); + if (buffer) { + if (size == sb.len) + match = memcmp(buffer, sb.buf, size); + free(buffer); + } + strbuf_release(&sb); + return match; +} + +static int ce_compare_gitlink(const struct cache_entry *ce) +{ + struct object_id oid; + + /* + * We don't actually require that the .git directory + * under GITLINK directory be a valid git directory. It + * might even be missing (in case nobody populated that + * sub-project). + * + * If so, we consider it always to match. + */ + if (resolve_gitlink_ref(ce->name, "HEAD", &oid) < 0) + return 0; + return !oideq(&oid, &ce->oid); +} + +static int ce_modified_check_fs(struct index_state *istate, + const struct cache_entry *ce, + struct stat *st) +{ + switch (st->st_mode & S_IFMT) { + case S_IFREG: + if (ce_compare_data(istate, ce, st)) + return DATA_CHANGED; + break; + case S_IFLNK: + if (ce_compare_link(ce, xsize_t(st->st_size))) + return DATA_CHANGED; + break; + case S_IFDIR: + if (S_ISGITLINK(ce->ce_mode)) + return ce_compare_gitlink(ce) ? DATA_CHANGED : 0; + /* else fallthrough */ + default: + return TYPE_CHANGED; + } + return 0; +} + +static int ce_match_stat_basic(const struct cache_entry *ce, struct stat *st) +{ + unsigned int changed = 0; + + if (ce->ce_flags & CE_REMOVE) + return MODE_CHANGED | DATA_CHANGED | TYPE_CHANGED; + + switch (ce->ce_mode & S_IFMT) { + case S_IFREG: + changed |= !S_ISREG(st->st_mode) ? TYPE_CHANGED : 0; + /* We consider only the owner x bit to be relevant for + * "mode changes" + */ + if (trust_executable_bit && + (0100 & (ce->ce_mode ^ st->st_mode))) + changed |= MODE_CHANGED; + break; + case S_IFLNK: + if (!S_ISLNK(st->st_mode) && + (has_symlinks || !S_ISREG(st->st_mode))) + changed |= TYPE_CHANGED; + break; + case S_IFGITLINK: + /* We ignore most of the st_xxx fields for gitlinks */ + if (!S_ISDIR(st->st_mode)) + changed |= TYPE_CHANGED; + else if (ce_compare_gitlink(ce)) + changed |= DATA_CHANGED; + return changed; + default: + BUG("unsupported ce_mode: %o", ce->ce_mode); + } + + changed |= match_stat_data(&ce->ce_stat_data, st); + + /* Racily smudged entry? */ + if (!ce->ce_stat_data.sd_size) { + if (!is_empty_blob_sha1(ce->oid.hash)) + changed |= DATA_CHANGED; + } + + return changed; +} + +static int is_racy_stat(const struct index_state *istate, + const struct stat_data *sd) +{ + return (istate->timestamp.sec && +#ifdef USE_NSEC + /* nanosecond timestamped files can also be racy! */ + (istate->timestamp.sec < sd->sd_mtime.sec || + (istate->timestamp.sec == sd->sd_mtime.sec && + istate->timestamp.nsec <= sd->sd_mtime.nsec)) +#else + istate->timestamp.sec <= sd->sd_mtime.sec +#endif + ); +} + +int is_racy_timestamp(const struct index_state *istate, + const struct cache_entry *ce) +{ + return (!S_ISGITLINK(ce->ce_mode) && + is_racy_stat(istate, &ce->ce_stat_data)); +} + +int match_stat_data_racy(const struct index_state *istate, + const struct stat_data *sd, struct stat *st) +{ + if (is_racy_stat(istate, sd)) + return MTIME_CHANGED; + return match_stat_data(sd, st); +} + +int ie_match_stat(struct index_state *istate, + const struct cache_entry *ce, struct stat *st, + unsigned int options) +{ + unsigned int changed; + int ignore_valid = options & CE_MATCH_IGNORE_VALID; + int ignore_skip_worktree = options & CE_MATCH_IGNORE_SKIP_WORKTREE; + int assume_racy_is_modified = options & CE_MATCH_RACY_IS_DIRTY; + int ignore_fsmonitor = options & CE_MATCH_IGNORE_FSMONITOR; + + if (!ignore_fsmonitor) + refresh_fsmonitor(istate); + /* + * If it's marked as always valid in the index, it's + * valid whatever the checked-out copy says. + * + * skip-worktree has the same effect with higher precedence + */ + if (!ignore_skip_worktree && ce_skip_worktree(ce)) + return 0; + if (!ignore_valid && (ce->ce_flags & CE_VALID)) + return 0; + if (!ignore_fsmonitor && (ce->ce_flags & CE_FSMONITOR_VALID)) + return 0; + + /* + * Intent-to-add entries have not been added, so the index entry + * by definition never matches what is in the work tree until it + * actually gets added. + */ + if (ce_intent_to_add(ce)) + return DATA_CHANGED | TYPE_CHANGED | MODE_CHANGED; + + changed = ce_match_stat_basic(ce, st); + + /* + * Within 1 second of this sequence: + * echo xyzzy >file && git-update-index --add file + * running this command: + * echo frotz >file + * would give a falsely clean cache entry. The mtime and + * length match the cache, and other stat fields do not change. + * + * We could detect this at update-index time (the cache entry + * being registered/updated records the same time as "now") + * and delay the return from git-update-index, but that would + * effectively mean we can make at most one commit per second, + * which is not acceptable. Instead, we check cache entries + * whose mtime are the same as the index file timestamp more + * carefully than others. + */ + if (!changed && is_racy_timestamp(istate, ce)) { + if (assume_racy_is_modified) + changed |= DATA_CHANGED; + else + changed |= ce_modified_check_fs(istate, ce, st); + } + + return changed; +} + +int ie_modified(struct index_state *istate, + const struct cache_entry *ce, + struct stat *st, unsigned int options) +{ + int changed, changed_fs; + + changed = ie_match_stat(istate, ce, st, options); + if (!changed) + return 0; + /* + * If the mode or type has changed, there's no point in trying + * to refresh the entry - it's not going to match + */ + if (changed & (MODE_CHANGED | TYPE_CHANGED)) + return changed; + + /* + * Immediately after read-tree or update-index --cacheinfo, + * the length field is zero, as we have never even read the + * lstat(2) information once, and we cannot trust DATA_CHANGED + * returned by ie_match_stat() which in turn was returned by + * ce_match_stat_basic() to signal that the filesize of the + * blob changed. We have to actually go to the filesystem to + * see if the contents match, and if so, should answer "unchanged". + * + * The logic does not apply to gitlinks, as ce_match_stat_basic() + * already has checked the actual HEAD from the filesystem in the + * subproject. If ie_match_stat() already said it is different, + * then we know it is. + */ + if ((changed & DATA_CHANGED) && + (S_ISGITLINK(ce->ce_mode) || ce->ce_stat_data.sd_size != 0)) + return changed; + + changed_fs = ce_modified_check_fs(istate, ce, st); + if (changed_fs) + return changed | changed_fs; + return 0; +} + +int base_name_compare(const char *name1, int len1, int mode1, + const char *name2, int len2, int mode2) +{ + unsigned char c1, c2; + int len = len1 < len2 ? len1 : len2; + int cmp; + + cmp = memcmp(name1, name2, len); + if (cmp) + return cmp; + c1 = name1[len]; + c2 = name2[len]; + if (!c1 && S_ISDIR(mode1)) + c1 = '/'; + if (!c2 && S_ISDIR(mode2)) + c2 = '/'; + return (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0; +} + +/* + * df_name_compare() is identical to base_name_compare(), except it + * compares conflicting directory/file entries as equal. Note that + * while a directory name compares as equal to a regular file, they + * then individually compare _differently_ to a filename that has + * a dot after the basename (because '\0' < '.' < '/'). + * + * This is used by routines that want to traverse the git namespace + * but then handle conflicting entries together when possible. + */ +int df_name_compare(const char *name1, int len1, int mode1, + const char *name2, int len2, int mode2) +{ + int len = len1 < len2 ? len1 : len2, cmp; + unsigned char c1, c2; + + cmp = memcmp(name1, name2, len); + if (cmp) + return cmp; + /* Directories and files compare equal (same length, same name) */ + if (len1 == len2) + return 0; + c1 = name1[len]; + if (!c1 && S_ISDIR(mode1)) + c1 = '/'; + c2 = name2[len]; + if (!c2 && S_ISDIR(mode2)) + c2 = '/'; + if (c1 == '/' && !c2) + return 0; + if (c2 == '/' && !c1) + return 0; + return c1 - c2; +} + +int name_compare(const char *name1, size_t len1, const char *name2, size_t len2) +{ + size_t min_len = (len1 < len2) ? len1 : len2; + int cmp = memcmp(name1, name2, min_len); + if (cmp) + return cmp; + if (len1 < len2) + return -1; + if (len1 > len2) + return 1; + return 0; +} + +int cache_name_stage_compare(const char *name1, int len1, int stage1, const char *name2, int len2, int stage2) +{ + int cmp; + + cmp = name_compare(name1, len1, name2, len2); + if (cmp) + return cmp; + + if (stage1 < stage2) + return -1; + if (stage1 > stage2) + return 1; + return 0; +} + +static int index_name_stage_pos(const struct index_state *istate, const char *name, int namelen, int stage) +{ + int first, last; + + first = 0; + last = istate->cache_nr; + while (last > first) { + int next = first + ((last - first) >> 1); + struct cache_entry *ce = istate->cache[next]; + int cmp = cache_name_stage_compare(name, namelen, stage, ce->name, ce_namelen(ce), ce_stage(ce)); + if (!cmp) + return next; + if (cmp < 0) { + last = next; + continue; + } + first = next+1; + } + return -first-1; +} + +int index_name_pos(const struct index_state *istate, const char *name, int namelen) +{ + return index_name_stage_pos(istate, name, namelen, 0); +} + +int remove_index_entry_at(struct index_state *istate, int pos) +{ + struct cache_entry *ce = istate->cache[pos]; + + record_resolve_undo(istate, ce); + remove_name_hash(istate, ce); + save_or_free_index_entry(istate, ce); + istate->cache_changed |= CE_ENTRY_REMOVED; + istate->cache_nr--; + if (pos >= istate->cache_nr) + return 0; + MOVE_ARRAY(istate->cache + pos, istate->cache + pos + 1, + istate->cache_nr - pos); + return 1; +} + +/* + * Remove all cache entries marked for removal, that is where + * CE_REMOVE is set in ce_flags. This is much more effective than + * calling remove_index_entry_at() for each entry to be removed. + */ +void remove_marked_cache_entries(struct index_state *istate, int invalidate) +{ + struct cache_entry **ce_array = istate->cache; + unsigned int i, j; + + for (i = j = 0; i < istate->cache_nr; i++) { + if (ce_array[i]->ce_flags & CE_REMOVE) { + if (invalidate) { + cache_tree_invalidate_path(istate, + ce_array[i]->name); + untracked_cache_remove_from_index(istate, + ce_array[i]->name); + } + remove_name_hash(istate, ce_array[i]); + save_or_free_index_entry(istate, ce_array[i]); + } + else + ce_array[j++] = ce_array[i]; + } + if (j == istate->cache_nr) + return; + istate->cache_changed |= CE_ENTRY_REMOVED; + istate->cache_nr = j; +} + +int remove_file_from_index(struct index_state *istate, const char *path) +{ + int pos = index_name_pos(istate, path, strlen(path)); + if (pos < 0) + pos = -pos-1; + cache_tree_invalidate_path(istate, path); + untracked_cache_remove_from_index(istate, path); + while (pos < istate->cache_nr && !strcmp(istate->cache[pos]->name, path)) + remove_index_entry_at(istate, pos); + return 0; +} + +static int compare_name(struct cache_entry *ce, const char *path, int namelen) +{ + return namelen != ce_namelen(ce) || memcmp(path, ce->name, namelen); +} + +static int index_name_pos_also_unmerged(struct index_state *istate, + const char *path, int namelen) +{ + int pos = index_name_pos(istate, path, namelen); + struct cache_entry *ce; + + if (pos >= 0) + return pos; + + /* maybe unmerged? */ + pos = -1 - pos; + if (pos >= istate->cache_nr || + compare_name((ce = istate->cache[pos]), path, namelen)) + return -1; + + /* order of preference: stage 2, 1, 3 */ + if (ce_stage(ce) == 1 && pos + 1 < istate->cache_nr && + ce_stage((ce = istate->cache[pos + 1])) == 2 && + !compare_name(ce, path, namelen)) + pos++; + return pos; +} + +static int different_name(struct cache_entry *ce, struct cache_entry *alias) +{ + int len = ce_namelen(ce); + return ce_namelen(alias) != len || memcmp(ce->name, alias->name, len); +} + +/* + * If we add a filename that aliases in the cache, we will use the + * name that we already have - but we don't want to update the same + * alias twice, because that implies that there were actually two + * different files with aliasing names! + * + * So we use the CE_ADDED flag to verify that the alias was an old + * one before we accept it as + */ +static struct cache_entry *create_alias_ce(struct index_state *istate, + struct cache_entry *ce, + struct cache_entry *alias) +{ + int len; + struct cache_entry *new_entry; + + if (alias->ce_flags & CE_ADDED) + die(_("will not add file alias '%s' ('%s' already exists in index)"), + ce->name, alias->name); + + /* Ok, create the new entry using the name of the existing alias */ + len = ce_namelen(alias); + new_entry = make_empty_cache_entry(istate, len); + memcpy(new_entry->name, alias->name, len); + copy_cache_entry(new_entry, ce); + save_or_free_index_entry(istate, ce); + return new_entry; +} + +void set_object_name_for_intent_to_add_entry(struct cache_entry *ce) +{ + struct object_id oid; + if (write_object_file("", 0, blob_type, &oid)) + die(_("cannot create an empty blob in the object database")); + oidcpy(&ce->oid, &oid); +} + +int add_to_index(struct index_state *istate, const char *path, struct stat *st, int flags) +{ + int namelen, was_same; + mode_t st_mode = st->st_mode; + struct cache_entry *ce, *alias = NULL; + unsigned ce_option = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE|CE_MATCH_RACY_IS_DIRTY; + int verbose = flags & (ADD_CACHE_VERBOSE | ADD_CACHE_PRETEND); + int pretend = flags & ADD_CACHE_PRETEND; + int intent_only = flags & ADD_CACHE_INTENT; + int add_option = (ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE| + (intent_only ? ADD_CACHE_NEW_ONLY : 0)); + int hash_flags = HASH_WRITE_OBJECT; + struct object_id oid; + + if (flags & ADD_CACHE_RENORMALIZE) + hash_flags |= HASH_RENORMALIZE; + + if (!S_ISREG(st_mode) && !S_ISLNK(st_mode) && !S_ISDIR(st_mode)) + return error(_("%s: can only add regular files, symbolic links or git-directories"), path); + + namelen = strlen(path); + if (S_ISDIR(st_mode)) { + if (resolve_gitlink_ref(path, "HEAD", &oid) < 0) + return error(_("'%s' does not have a commit checked out"), path); + while (namelen && path[namelen-1] == '/') + namelen--; + } + ce = make_empty_cache_entry(istate, namelen); + memcpy(ce->name, path, namelen); + ce->ce_namelen = namelen; + if (!intent_only) + fill_stat_cache_info(istate, ce, st); + else + ce->ce_flags |= CE_INTENT_TO_ADD; + + + if (trust_executable_bit && has_symlinks) { + ce->ce_mode = create_ce_mode(st_mode); + } else { + /* If there is an existing entry, pick the mode bits and type + * from it, otherwise assume unexecutable regular file. + */ + struct cache_entry *ent; + int pos = index_name_pos_also_unmerged(istate, path, namelen); + + ent = (0 <= pos) ? istate->cache[pos] : NULL; + ce->ce_mode = ce_mode_from_stat(ent, st_mode); + } + + /* When core.ignorecase=true, determine if a directory of the same name but differing + * case already exists within the Git repository. If it does, ensure the directory + * case of the file being added to the repository matches (is folded into) the existing + * entry's directory case. + */ + if (ignore_case) { + adjust_dirname_case(istate, ce->name); + } + if (!(flags & ADD_CACHE_RENORMALIZE)) { + alias = index_file_exists(istate, ce->name, + ce_namelen(ce), ignore_case); + if (alias && + !ce_stage(alias) && + !ie_match_stat(istate, alias, st, ce_option)) { + /* Nothing changed, really */ + if (!S_ISGITLINK(alias->ce_mode)) + ce_mark_uptodate(alias); + alias->ce_flags |= CE_ADDED; + + discard_cache_entry(ce); + return 0; + } + } + if (!intent_only) { + if (index_path(istate, &ce->oid, path, st, hash_flags)) { + discard_cache_entry(ce); + return error(_("unable to index file '%s'"), path); + } + } else + set_object_name_for_intent_to_add_entry(ce); + + if (ignore_case && alias && different_name(ce, alias)) + ce = create_alias_ce(istate, ce, alias); + ce->ce_flags |= CE_ADDED; + + /* It was suspected to be racily clean, but it turns out to be Ok */ + was_same = (alias && + !ce_stage(alias) && + oideq(&alias->oid, &ce->oid) && + ce->ce_mode == alias->ce_mode); + + if (pretend) + discard_cache_entry(ce); + else if (add_index_entry(istate, ce, add_option)) { + discard_cache_entry(ce); + return error(_("unable to add '%s' to index"), path); + } + if (verbose && !was_same) + printf("add '%s'\n", path); + return 0; +} + +int add_file_to_index(struct index_state *istate, const char *path, int flags) +{ + struct stat st; + if (lstat(path, &st)) + die_errno(_("unable to stat '%s'"), path); + return add_to_index(istate, path, &st, flags); +} + +struct cache_entry *make_empty_cache_entry(struct index_state *istate, size_t len) +{ + return mem_pool__ce_calloc(find_mem_pool(istate), len); +} + +struct cache_entry *make_empty_transient_cache_entry(size_t len) +{ + return xcalloc(1, cache_entry_size(len)); +} + +struct cache_entry *make_cache_entry(struct index_state *istate, + unsigned int mode, + const struct object_id *oid, + const char *path, + int stage, + unsigned int refresh_options) +{ + struct cache_entry *ce, *ret; + int len; + + if (!verify_path(path, mode)) { + error(_("invalid path '%s'"), path); + return NULL; + } + + len = strlen(path); + ce = make_empty_cache_entry(istate, len); + + oidcpy(&ce->oid, oid); + memcpy(ce->name, path, len); + ce->ce_flags = create_ce_flags(stage); + ce->ce_namelen = len; + ce->ce_mode = create_ce_mode(mode); + + ret = refresh_cache_entry(istate, ce, refresh_options); + if (ret != ce) + discard_cache_entry(ce); + return ret; +} + +struct cache_entry *make_transient_cache_entry(unsigned int mode, const struct object_id *oid, + const char *path, int stage) +{ + struct cache_entry *ce; + int len; + + if (!verify_path(path, mode)) { + error(_("invalid path '%s'"), path); + return NULL; + } + + len = strlen(path); + ce = make_empty_transient_cache_entry(len); + + oidcpy(&ce->oid, oid); + memcpy(ce->name, path, len); + ce->ce_flags = create_ce_flags(stage); + ce->ce_namelen = len; + ce->ce_mode = create_ce_mode(mode); + + return ce; +} + +/* + * Chmod an index entry with either +x or -x. + * + * Returns -1 if the chmod for the particular cache entry failed (if it's + * not a regular file), -2 if an invalid flip argument is passed in, 0 + * otherwise. + */ +int chmod_index_entry(struct index_state *istate, struct cache_entry *ce, + char flip) +{ + if (!S_ISREG(ce->ce_mode)) + return -1; + switch (flip) { + case '+': + ce->ce_mode |= 0111; + break; + case '-': + ce->ce_mode &= ~0111; + break; + default: + return -2; + } + cache_tree_invalidate_path(istate, ce->name); + ce->ce_flags |= CE_UPDATE_IN_BASE; + mark_fsmonitor_invalid(istate, ce); + istate->cache_changed |= CE_ENTRY_CHANGED; + + return 0; +} + +int ce_same_name(const struct cache_entry *a, const struct cache_entry *b) +{ + int len = ce_namelen(a); + return ce_namelen(b) == len && !memcmp(a->name, b->name, len); +} + +/* + * We fundamentally don't like some paths: we don't want + * dot or dot-dot anywhere, and for obvious reasons don't + * want to recurse into ".git" either. + * + * Also, we don't want double slashes or slashes at the + * end that can make pathnames ambiguous. + */ +static int verify_dotfile(const char *rest, unsigned mode) +{ + /* + * The first character was '.', but that + * has already been discarded, we now test + * the rest. + */ + + /* "." is not allowed */ + if (*rest == '\0' || is_dir_sep(*rest)) + return 0; + + switch (*rest) { + /* + * ".git" followed by NUL or slash is bad. Note that we match + * case-insensitively here, even if ignore_case is not set. + * This outlaws ".GIT" everywhere out of an abundance of caution, + * since there's really no good reason to allow it. + * + * Once we've seen ".git", we can also find ".gitmodules", etc (also + * case-insensitively). + */ + case 'g': + case 'G': + if (rest[1] != 'i' && rest[1] != 'I') + break; + if (rest[2] != 't' && rest[2] != 'T') + break; + if (rest[3] == '\0' || is_dir_sep(rest[3])) + return 0; + if (S_ISLNK(mode)) { + rest += 3; + if (skip_iprefix(rest, "modules", &rest) && + (*rest == '\0' || is_dir_sep(*rest))) + return 0; + } + break; + case '.': + if (rest[1] == '\0' || is_dir_sep(rest[1])) + return 0; + } + return 1; +} + +int verify_path(const char *path, unsigned mode) +{ + char c; + + if (has_dos_drive_prefix(path)) + return 0; + + goto inside; + for (;;) { + if (!c) + return 1; + if (is_dir_sep(c)) { +inside: + if (protect_hfs) { + if (is_hfs_dotgit(path)) + return 0; + if (S_ISLNK(mode)) { + if (is_hfs_dotgitmodules(path)) + return 0; + } + } + if (protect_ntfs) { + if (is_ntfs_dotgit(path)) + return 0; + if (S_ISLNK(mode)) { + if (is_ntfs_dotgitmodules(path)) + return 0; + } + } + + c = *path++; + if ((c == '.' && !verify_dotfile(path, mode)) || + is_dir_sep(c) || c == '\0') + return 0; + } + c = *path++; + } +} + +/* + * Do we have another file that has the beginning components being a + * proper superset of the name we're trying to add? + */ +static int has_file_name(struct index_state *istate, + const struct cache_entry *ce, int pos, int ok_to_replace) +{ + int retval = 0; + int len = ce_namelen(ce); + int stage = ce_stage(ce); + const char *name = ce->name; + + while (pos < istate->cache_nr) { + struct cache_entry *p = istate->cache[pos++]; + + if (len >= ce_namelen(p)) + break; + if (memcmp(name, p->name, len)) + break; + if (ce_stage(p) != stage) + continue; + if (p->name[len] != '/') + continue; + if (p->ce_flags & CE_REMOVE) + continue; + retval = -1; + if (!ok_to_replace) + break; + remove_index_entry_at(istate, --pos); + } + return retval; +} + + +/* + * Like strcmp(), but also return the offset of the first change. + * If strings are equal, return the length. + */ +int strcmp_offset(const char *s1, const char *s2, size_t *first_change) +{ + size_t k; + + if (!first_change) + return strcmp(s1, s2); + + for (k = 0; s1[k] == s2[k]; k++) + if (s1[k] == '\0') + break; + + *first_change = k; + return (unsigned char)s1[k] - (unsigned char)s2[k]; +} + +/* + * Do we have another file with a pathname that is a proper + * subset of the name we're trying to add? + * + * That is, is there another file in the index with a path + * that matches a sub-directory in the given entry? + */ +static int has_dir_name(struct index_state *istate, + const struct cache_entry *ce, int pos, int ok_to_replace) +{ + int retval = 0; + int stage = ce_stage(ce); + const char *name = ce->name; + const char *slash = name + ce_namelen(ce); + size_t len_eq_last; + int cmp_last = 0; + + /* + * We are frequently called during an iteration on a sorted + * list of pathnames and while building a new index. Therefore, + * there is a high probability that this entry will eventually + * be appended to the index, rather than inserted in the middle. + * If we can confirm that, we can avoid binary searches on the + * components of the pathname. + * + * Compare the entry's full path with the last path in the index. + */ + if (istate->cache_nr > 0) { + cmp_last = strcmp_offset(name, + istate->cache[istate->cache_nr - 1]->name, + &len_eq_last); + if (cmp_last > 0) { + if (len_eq_last == 0) { + /* + * The entry sorts AFTER the last one in the + * index and their paths have no common prefix, + * so there cannot be a F/D conflict. + */ + return retval; + } else { + /* + * The entry sorts AFTER the last one in the + * index, but has a common prefix. Fall through + * to the loop below to disect the entry's path + * and see where the difference is. + */ + } + } else if (cmp_last == 0) { + /* + * The entry exactly matches the last one in the + * index, but because of multiple stage and CE_REMOVE + * items, we fall through and let the regular search + * code handle it. + */ + } + } + + for (;;) { + size_t len; + + for (;;) { + if (*--slash == '/') + break; + if (slash <= ce->name) + return retval; + } + len = slash - name; + + if (cmp_last > 0) { + /* + * (len + 1) is a directory boundary (including + * the trailing slash). And since the loop is + * decrementing "slash", the first iteration is + * the longest directory prefix; subsequent + * iterations consider parent directories. + */ + + if (len + 1 <= len_eq_last) { + /* + * The directory prefix (including the trailing + * slash) also appears as a prefix in the last + * entry, so the remainder cannot collide (because + * strcmp said the whole path was greater). + * + * EQ: last: xxx/A + * this: xxx/B + * + * LT: last: xxx/file_A + * this: xxx/file_B + */ + return retval; + } + + if (len > len_eq_last) { + /* + * This part of the directory prefix (excluding + * the trailing slash) is longer than the known + * equal portions, so this sub-directory cannot + * collide with a file. + * + * GT: last: xxxA + * this: xxxB/file + */ + return retval; + } + + if (istate->cache_nr > 0 && + ce_namelen(istate->cache[istate->cache_nr - 1]) > len) { + /* + * The directory prefix lines up with part of + * a longer file or directory name, but sorts + * after it, so this sub-directory cannot + * collide with a file. + * + * last: xxx/yy-file (because '-' sorts before '/') + * this: xxx/yy/abc + */ + return retval; + } + + /* + * This is a possible collision. Fall through and + * let the regular search code handle it. + * + * last: xxx + * this: xxx/file + */ + } + + pos = index_name_stage_pos(istate, name, len, stage); + if (pos >= 0) { + /* + * Found one, but not so fast. This could + * be a marker that says "I was here, but + * I am being removed". Such an entry is + * not a part of the resulting tree, and + * it is Ok to have a directory at the same + * path. + */ + if (!(istate->cache[pos]->ce_flags & CE_REMOVE)) { + retval = -1; + if (!ok_to_replace) + break; + remove_index_entry_at(istate, pos); + continue; + } + } + else + pos = -pos-1; + + /* + * Trivial optimization: if we find an entry that + * already matches the sub-directory, then we know + * we're ok, and we can exit. + */ + while (pos < istate->cache_nr) { + struct cache_entry *p = istate->cache[pos]; + if ((ce_namelen(p) <= len) || + (p->name[len] != '/') || + memcmp(p->name, name, len)) + break; /* not our subdirectory */ + if (ce_stage(p) == stage && !(p->ce_flags & CE_REMOVE)) + /* + * p is at the same stage as our entry, and + * is a subdirectory of what we are looking + * at, so we cannot have conflicts at our + * level or anything shorter. + */ + return retval; + pos++; + } + } + return retval; +} + +/* We may be in a situation where we already have path/file and path + * is being added, or we already have path and path/file is being + * added. Either one would result in a nonsense tree that has path + * twice when git-write-tree tries to write it out. Prevent it. + * + * If ok-to-replace is specified, we remove the conflicting entries + * from the cache so the caller should recompute the insert position. + * When this happens, we return non-zero. + */ +static int check_file_directory_conflict(struct index_state *istate, + const struct cache_entry *ce, + int pos, int ok_to_replace) +{ + int retval; + + /* + * When ce is an "I am going away" entry, we allow it to be added + */ + if (ce->ce_flags & CE_REMOVE) + return 0; + + /* + * We check if the path is a sub-path of a subsequent pathname + * first, since removing those will not change the position + * in the array. + */ + retval = has_file_name(istate, ce, pos, ok_to_replace); + + /* + * Then check if the path might have a clashing sub-directory + * before it. + */ + return retval + has_dir_name(istate, ce, pos, ok_to_replace); +} + +static int add_index_entry_with_check(struct index_state *istate, struct cache_entry *ce, int option) +{ + int pos; + int ok_to_add = option & ADD_CACHE_OK_TO_ADD; + int ok_to_replace = option & ADD_CACHE_OK_TO_REPLACE; + int skip_df_check = option & ADD_CACHE_SKIP_DFCHECK; + int new_only = option & ADD_CACHE_NEW_ONLY; + + if (!(option & ADD_CACHE_KEEP_CACHE_TREE)) + cache_tree_invalidate_path(istate, ce->name); + + /* + * If this entry's path sorts after the last entry in the index, + * we can avoid searching for it. + */ + if (istate->cache_nr > 0 && + strcmp(ce->name, istate->cache[istate->cache_nr - 1]->name) > 0) + pos = -istate->cache_nr - 1; + else + pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce)); + + /* existing match? Just replace it. */ + if (pos >= 0) { + if (!new_only) + replace_index_entry(istate, pos, ce); + return 0; + } + pos = -pos-1; + + if (!(option & ADD_CACHE_KEEP_CACHE_TREE)) + untracked_cache_add_to_index(istate, ce->name); + + /* + * Inserting a merged entry ("stage 0") into the index + * will always replace all non-merged entries.. + */ + if (pos < istate->cache_nr && ce_stage(ce) == 0) { + while (ce_same_name(istate->cache[pos], ce)) { + ok_to_add = 1; + if (!remove_index_entry_at(istate, pos)) + break; + } + } + + if (!ok_to_add) + return -1; + if (!verify_path(ce->name, ce->ce_mode)) + return error(_("invalid path '%s'"), ce->name); + + if (!skip_df_check && + check_file_directory_conflict(istate, ce, pos, ok_to_replace)) { + if (!ok_to_replace) + return error(_("'%s' appears as both a file and as a directory"), + ce->name); + pos = index_name_stage_pos(istate, ce->name, ce_namelen(ce), ce_stage(ce)); + pos = -pos-1; + } + return pos + 1; +} + +int add_index_entry(struct index_state *istate, struct cache_entry *ce, int option) +{ + int pos; + + if (option & ADD_CACHE_JUST_APPEND) + pos = istate->cache_nr; + else { + int ret; + ret = add_index_entry_with_check(istate, ce, option); + if (ret <= 0) + return ret; + pos = ret - 1; + } + + /* Make sure the array is big enough .. */ + ALLOC_GROW(istate->cache, istate->cache_nr + 1, istate->cache_alloc); + + /* Add it in.. */ + istate->cache_nr++; + if (istate->cache_nr > pos + 1) + MOVE_ARRAY(istate->cache + pos + 1, istate->cache + pos, + istate->cache_nr - pos - 1); + set_index_entry(istate, pos, ce); + istate->cache_changed |= CE_ENTRY_ADDED; + return 0; +} + +/* + * "refresh" does not calculate a new sha1 file or bring the + * cache up-to-date for mode/content changes. But what it + * _does_ do is to "re-match" the stat information of a file + * with the cache, so that you can refresh the cache for a + * file that hasn't been changed but where the stat entry is + * out of date. + * + * For example, you'd want to do this after doing a "git-read-tree", + * to link up the stat cache details with the proper files. + */ +static struct cache_entry *refresh_cache_ent(struct index_state *istate, + struct cache_entry *ce, + unsigned int options, int *err, + int *changed_ret) +{ + struct stat st; + struct cache_entry *updated; + int changed; + int refresh = options & CE_MATCH_REFRESH; + int ignore_valid = options & CE_MATCH_IGNORE_VALID; + int ignore_skip_worktree = options & CE_MATCH_IGNORE_SKIP_WORKTREE; + int ignore_missing = options & CE_MATCH_IGNORE_MISSING; + int ignore_fsmonitor = options & CE_MATCH_IGNORE_FSMONITOR; + + if (!refresh || ce_uptodate(ce)) + return ce; + + if (!ignore_fsmonitor) + refresh_fsmonitor(istate); + /* + * CE_VALID or CE_SKIP_WORKTREE means the user promised us + * that the change to the work tree does not matter and told + * us not to worry. + */ + if (!ignore_skip_worktree && ce_skip_worktree(ce)) { + ce_mark_uptodate(ce); + return ce; + } + if (!ignore_valid && (ce->ce_flags & CE_VALID)) { + ce_mark_uptodate(ce); + return ce; + } + if (!ignore_fsmonitor && (ce->ce_flags & CE_FSMONITOR_VALID)) { + ce_mark_uptodate(ce); + return ce; + } + + if (has_symlink_leading_path(ce->name, ce_namelen(ce))) { + if (ignore_missing) + return ce; + if (err) + *err = ENOENT; + return NULL; + } + + if (lstat(ce->name, &st) < 0) { + if (ignore_missing && errno == ENOENT) + return ce; + if (err) + *err = errno; + return NULL; + } + + changed = ie_match_stat(istate, ce, &st, options); + if (changed_ret) + *changed_ret = changed; + if (!changed) { + /* + * The path is unchanged. If we were told to ignore + * valid bit, then we did the actual stat check and + * found that the entry is unmodified. If the entry + * is not marked VALID, this is the place to mark it + * valid again, under "assume unchanged" mode. + */ + if (ignore_valid && assume_unchanged && + !(ce->ce_flags & CE_VALID)) + ; /* mark this one VALID again */ + else { + /* + * We do not mark the index itself "modified" + * because CE_UPTODATE flag is in-core only; + * we are not going to write this change out. + */ + if (!S_ISGITLINK(ce->ce_mode)) { + ce_mark_uptodate(ce); + mark_fsmonitor_valid(istate, ce); + } + return ce; + } + } + + if (ie_modified(istate, ce, &st, options)) { + if (err) + *err = EINVAL; + return NULL; + } + + updated = make_empty_cache_entry(istate, ce_namelen(ce)); + copy_cache_entry(updated, ce); + memcpy(updated->name, ce->name, ce->ce_namelen + 1); + fill_stat_cache_info(istate, updated, &st); + /* + * If ignore_valid is not set, we should leave CE_VALID bit + * alone. Otherwise, paths marked with --no-assume-unchanged + * (i.e. things to be edited) will reacquire CE_VALID bit + * automatically, which is not really what we want. + */ + if (!ignore_valid && assume_unchanged && + !(ce->ce_flags & CE_VALID)) + updated->ce_flags &= ~CE_VALID; + + /* istate->cache_changed is updated in the caller */ + return updated; +} + +static void show_file(const char * fmt, const char * name, int in_porcelain, + int * first, const char *header_msg) +{ + if (in_porcelain && *first && header_msg) { + printf("%s\n", header_msg); + *first = 0; + } + printf(fmt, name); +} + +int refresh_index(struct index_state *istate, unsigned int flags, + const struct pathspec *pathspec, + char *seen, const char *header_msg) +{ + int i; + int has_errors = 0; + int really = (flags & REFRESH_REALLY) != 0; + int allow_unmerged = (flags & REFRESH_UNMERGED) != 0; + int quiet = (flags & REFRESH_QUIET) != 0; + int not_new = (flags & REFRESH_IGNORE_MISSING) != 0; + int ignore_submodules = (flags & REFRESH_IGNORE_SUBMODULES) != 0; + int first = 1; + int in_porcelain = (flags & REFRESH_IN_PORCELAIN); + unsigned int options = (CE_MATCH_REFRESH | + (really ? CE_MATCH_IGNORE_VALID : 0) | + (not_new ? CE_MATCH_IGNORE_MISSING : 0)); + const char *modified_fmt; + const char *deleted_fmt; + const char *typechange_fmt; + const char *added_fmt; + const char *unmerged_fmt; + struct progress *progress = NULL; + + if (flags & REFRESH_PROGRESS && isatty(2)) + progress = start_delayed_progress(_("Refresh index"), + istate->cache_nr); + + trace_performance_enter(); + modified_fmt = in_porcelain ? "M\t%s\n" : "%s: needs update\n"; + deleted_fmt = in_porcelain ? "D\t%s\n" : "%s: needs update\n"; + typechange_fmt = in_porcelain ? "T\t%s\n" : "%s: needs update\n"; + added_fmt = in_porcelain ? "A\t%s\n" : "%s: needs update\n"; + unmerged_fmt = in_porcelain ? "U\t%s\n" : "%s: needs merge\n"; + /* + * Use the multi-threaded preload_index() to refresh most of the + * cache entries quickly then in the single threaded loop below, + * we only have to do the special cases that are left. + */ + preload_index(istate, pathspec, 0); + for (i = 0; i < istate->cache_nr; i++) { + struct cache_entry *ce, *new_entry; + int cache_errno = 0; + int changed = 0; + int filtered = 0; + + ce = istate->cache[i]; + if (ignore_submodules && S_ISGITLINK(ce->ce_mode)) + continue; + + if (pathspec && !ce_path_match(istate, ce, pathspec, seen)) + filtered = 1; + + if (ce_stage(ce)) { + while ((i < istate->cache_nr) && + ! strcmp(istate->cache[i]->name, ce->name)) + i++; + i--; + if (allow_unmerged) + continue; + if (!filtered) + show_file(unmerged_fmt, ce->name, in_porcelain, + &first, header_msg); + has_errors = 1; + continue; + } + + if (filtered) + continue; + + new_entry = refresh_cache_ent(istate, ce, options, &cache_errno, &changed); + if (new_entry == ce) + continue; + if (progress) + display_progress(progress, i); + if (!new_entry) { + const char *fmt; + + if (really && cache_errno == EINVAL) { + /* If we are doing --really-refresh that + * means the index is not valid anymore. + */ + ce->ce_flags &= ~CE_VALID; + ce->ce_flags |= CE_UPDATE_IN_BASE; + mark_fsmonitor_invalid(istate, ce); + istate->cache_changed |= CE_ENTRY_CHANGED; + } + if (quiet) + continue; + + if (cache_errno == ENOENT) + fmt = deleted_fmt; + else if (ce_intent_to_add(ce)) + fmt = added_fmt; /* must be before other checks */ + else if (changed & TYPE_CHANGED) + fmt = typechange_fmt; + else + fmt = modified_fmt; + show_file(fmt, + ce->name, in_porcelain, &first, header_msg); + has_errors = 1; + continue; + } + + replace_index_entry(istate, i, new_entry); + } + if (progress) { + display_progress(progress, istate->cache_nr); + stop_progress(&progress); + } + trace_performance_leave("refresh index"); + return has_errors; +} + +struct cache_entry *refresh_cache_entry(struct index_state *istate, + struct cache_entry *ce, + unsigned int options) +{ + return refresh_cache_ent(istate, ce, options, NULL, NULL); +} + + +/***************************************************************** + * Index File I/O + *****************************************************************/ + +#define INDEX_FORMAT_DEFAULT 3 + +static unsigned int get_index_format_default(void) +{ + char *envversion = getenv("GIT_INDEX_VERSION"); + char *endp; + int value; + unsigned int version = INDEX_FORMAT_DEFAULT; + + if (!envversion) { + if (!git_config_get_int("index.version", &value)) + version = value; + if (version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < version) { + warning(_("index.version set, but the value is invalid.\n" + "Using version %i"), INDEX_FORMAT_DEFAULT); + return INDEX_FORMAT_DEFAULT; + } + return version; + } + + version = strtoul(envversion, &endp, 10); + if (*endp || + version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < version) { + warning(_("GIT_INDEX_VERSION set, but the value is invalid.\n" + "Using version %i"), INDEX_FORMAT_DEFAULT); + version = INDEX_FORMAT_DEFAULT; + } + return version; +} + +/* + * dev/ino/uid/gid/size are also just tracked to the low 32 bits + * Again - this is just a (very strong in practice) heuristic that + * the inode hasn't changed. + * + * We save the fields in big-endian order to allow using the + * index file over NFS transparently. + */ +struct ondisk_cache_entry { + struct cache_time ctime; + struct cache_time mtime; + uint32_t dev; + uint32_t ino; + uint32_t mode; + uint32_t uid; + uint32_t gid; + uint32_t size; + /* + * unsigned char hash[hashsz]; + * uint16_t flags; + * if (flags & CE_EXTENDED) + * uint16_t flags2; + */ + unsigned char data[GIT_MAX_RAWSZ + 2 * sizeof(uint16_t)]; + char name[FLEX_ARRAY]; +}; + +/* These are only used for v3 or lower */ +#define align_padding_size(size, len) ((size + (len) + 8) & ~7) - (size + len) +#define align_flex_name(STRUCT,len) ((offsetof(struct STRUCT,data) + (len) + 8) & ~7) +#define ondisk_cache_entry_size(len) align_flex_name(ondisk_cache_entry,len) +#define ondisk_data_size(flags, len) (the_hash_algo->rawsz + \ + ((flags & CE_EXTENDED) ? 2 : 1) * sizeof(uint16_t) + len) +#define ondisk_data_size_max(len) (ondisk_data_size(CE_EXTENDED, len)) +#define ondisk_ce_size(ce) (ondisk_cache_entry_size(ondisk_data_size((ce)->ce_flags, ce_namelen(ce)))) + +/* Allow fsck to force verification of the index checksum. */ +int verify_index_checksum; + +/* Allow fsck to force verification of the cache entry order. */ +int verify_ce_order; + +static int verify_hdr(const struct cache_header *hdr, unsigned long size) +{ + git_hash_ctx c; + unsigned char hash[GIT_MAX_RAWSZ]; + int hdr_version; + + if (hdr->hdr_signature != htonl(CACHE_SIGNATURE)) + return error(_("bad signature 0x%08x"), hdr->hdr_signature); + hdr_version = ntohl(hdr->hdr_version); + if (hdr_version < INDEX_FORMAT_LB || INDEX_FORMAT_UB < hdr_version) + return error(_("bad index version %d"), hdr_version); + + if (!verify_index_checksum) + return 0; + + the_hash_algo->init_fn(&c); + the_hash_algo->update_fn(&c, hdr, size - the_hash_algo->rawsz); + the_hash_algo->final_fn(hash, &c); + if (!hasheq(hash, (unsigned char *)hdr + size - the_hash_algo->rawsz)) + return error(_("bad index file sha1 signature")); + return 0; +} + +static int read_index_extension(struct index_state *istate, + const char *ext, const char *data, unsigned long sz) +{ + switch (CACHE_EXT(ext)) { + case CACHE_EXT_TREE: + istate->cache_tree = cache_tree_read(data, sz); + break; + case CACHE_EXT_RESOLVE_UNDO: + istate->resolve_undo = resolve_undo_read(data, sz); + break; + case CACHE_EXT_LINK: + if (read_link_extension(istate, data, sz)) + return -1; + break; + case CACHE_EXT_UNTRACKED: + istate->untracked = read_untracked_extension(data, sz); + break; + case CACHE_EXT_FSMONITOR: + read_fsmonitor_extension(istate, data, sz); + break; + case CACHE_EXT_ENDOFINDEXENTRIES: + case CACHE_EXT_INDEXENTRYOFFSETTABLE: + /* already handled in do_read_index() */ + break; + default: + if (*ext < 'A' || 'Z' < *ext) + return error(_("index uses %.4s extension, which we do not understand"), + ext); + fprintf_ln(stderr, _("ignoring %.4s extension"), ext); + break; + } + return 0; +} + +static struct cache_entry *create_from_disk(struct mem_pool *ce_mem_pool, + unsigned int version, + struct ondisk_cache_entry *ondisk, + unsigned long *ent_size, + const struct cache_entry *previous_ce) +{ + struct cache_entry *ce; + size_t len; + const char *name; + const unsigned hashsz = the_hash_algo->rawsz; + const uint16_t *flagsp = (const uint16_t *)(ondisk->data + hashsz); + unsigned int flags; + size_t copy_len = 0; + /* + * Adjacent cache entries tend to share the leading paths, so it makes + * sense to only store the differences in later entries. In the v4 + * on-disk format of the index, each on-disk cache entry stores the + * number of bytes to be stripped from the end of the previous name, + * and the bytes to append to the result, to come up with its name. + */ + int expand_name_field = version == 4; + + /* On-disk flags are just 16 bits */ + flags = get_be16(flagsp); + len = flags & CE_NAMEMASK; + + if (flags & CE_EXTENDED) { + int extended_flags; + extended_flags = get_be16(flagsp + 1) << 16; + /* We do not yet understand any bit out of CE_EXTENDED_FLAGS */ + if (extended_flags & ~CE_EXTENDED_FLAGS) + die(_("unknown index entry format 0x%08x"), extended_flags); + flags |= extended_flags; + name = (const char *)(flagsp + 2); + } + else + name = (const char *)(flagsp + 1); + + if (expand_name_field) { + const unsigned char *cp = (const unsigned char *)name; + size_t strip_len, previous_len; + + /* If we're at the begining of a block, ignore the previous name */ + strip_len = decode_varint(&cp); + if (previous_ce) { + previous_len = previous_ce->ce_namelen; + if (previous_len < strip_len) + die(_("malformed name field in the index, near path '%s'"), + previous_ce->name); + copy_len = previous_len - strip_len; + } + name = (const char *)cp; + } + + if (len == CE_NAMEMASK) { + len = strlen(name); + if (expand_name_field) + len += copy_len; + } + + ce = mem_pool__ce_alloc(ce_mem_pool, len); + + ce->ce_stat_data.sd_ctime.sec = get_be32(&ondisk->ctime.sec); + ce->ce_stat_data.sd_mtime.sec = get_be32(&ondisk->mtime.sec); + ce->ce_stat_data.sd_ctime.nsec = get_be32(&ondisk->ctime.nsec); + ce->ce_stat_data.sd_mtime.nsec = get_be32(&ondisk->mtime.nsec); + ce->ce_stat_data.sd_dev = get_be32(&ondisk->dev); + ce->ce_stat_data.sd_ino = get_be32(&ondisk->ino); + ce->ce_mode = get_be32(&ondisk->mode); + ce->ce_stat_data.sd_uid = get_be32(&ondisk->uid); + ce->ce_stat_data.sd_gid = get_be32(&ondisk->gid); + ce->ce_stat_data.sd_size = get_be32(&ondisk->size); + ce->ce_flags = flags & ~CE_NAMEMASK; + ce->ce_namelen = len; + ce->index = 0; + hashcpy(ce->oid.hash, ondisk->data); + memcpy(ce->name, name, len); + ce->name[len] = '\0'; + + if (expand_name_field) { + if (copy_len) + memcpy(ce->name, previous_ce->name, copy_len); + memcpy(ce->name + copy_len, name, len + 1 - copy_len); + *ent_size = (name - ((char *)ondisk)) + len + 1 - copy_len; + } else { + memcpy(ce->name, name, len + 1); + *ent_size = ondisk_ce_size(ce); + } + return ce; +} + +static void check_ce_order(struct index_state *istate) +{ + unsigned int i; + + if (!verify_ce_order) + return; + + for (i = 1; i < istate->cache_nr; i++) { + struct cache_entry *ce = istate->cache[i - 1]; + struct cache_entry *next_ce = istate->cache[i]; + int name_compare = strcmp(ce->name, next_ce->name); + + if (0 < name_compare) + die(_("unordered stage entries in index")); + if (!name_compare) { + if (!ce_stage(ce)) + die(_("multiple stage entries for merged file '%s'"), + ce->name); + if (ce_stage(ce) > ce_stage(next_ce)) + die(_("unordered stage entries for '%s'"), + ce->name); + } + } +} + +static void tweak_untracked_cache(struct index_state *istate) +{ + switch (git_config_get_untracked_cache()) { + case -1: /* keep: do nothing */ + break; + case 0: /* false */ + remove_untracked_cache(istate); + break; + case 1: /* true */ + add_untracked_cache(istate); + break; + default: /* unknown value: do nothing */ + break; + } +} + +static void tweak_split_index(struct index_state *istate) +{ + switch (git_config_get_split_index()) { + case -1: /* unset: do nothing */ + break; + case 0: /* false */ + remove_split_index(istate); + break; + case 1: /* true */ + add_split_index(istate); + break; + default: /* unknown value: do nothing */ + break; + } +} + +static void post_read_index_from(struct index_state *istate) +{ + check_ce_order(istate); + tweak_untracked_cache(istate); + tweak_split_index(istate); + tweak_fsmonitor(istate); +} + +static size_t estimate_cache_size_from_compressed(unsigned int entries) +{ + return entries * (sizeof(struct cache_entry) + CACHE_ENTRY_PATH_LENGTH); +} + +static size_t estimate_cache_size(size_t ondisk_size, unsigned int entries) +{ + long per_entry = sizeof(struct cache_entry) - sizeof(struct ondisk_cache_entry); + + /* + * Account for potential alignment differences. + */ + per_entry += align_padding_size(sizeof(struct cache_entry), -sizeof(struct ondisk_cache_entry)); + return ondisk_size + entries * per_entry; +} + +struct index_entry_offset +{ + /* starting byte offset into index file, count of index entries in this block */ + int offset, nr; +}; + +struct index_entry_offset_table +{ + int nr; + struct index_entry_offset entries[FLEX_ARRAY]; +}; + +static struct index_entry_offset_table *read_ieot_extension(const char *mmap, size_t mmap_size, size_t offset); +static void write_ieot_extension(struct strbuf *sb, struct index_entry_offset_table *ieot); + +static size_t read_eoie_extension(const char *mmap, size_t mmap_size); +static void write_eoie_extension(struct strbuf *sb, git_hash_ctx *eoie_context, size_t offset); + +struct load_index_extensions +{ + pthread_t pthread; + struct index_state *istate; + const char *mmap; + size_t mmap_size; + unsigned long src_offset; +}; + +static void *load_index_extensions(void *_data) +{ + struct load_index_extensions *p = _data; + unsigned long src_offset = p->src_offset; + + while (src_offset <= p->mmap_size - the_hash_algo->rawsz - 8) { + /* After an array of active_nr index entries, + * there can be arbitrary number of extended + * sections, each of which is prefixed with + * extension name (4-byte) and section length + * in 4-byte network byte order. + */ + uint32_t extsize = get_be32(p->mmap + src_offset + 4); + if (read_index_extension(p->istate, + p->mmap + src_offset, + p->mmap + src_offset + 8, + extsize) < 0) { + munmap((void *)p->mmap, p->mmap_size); + die(_("index file corrupt")); + } + src_offset += 8; + src_offset += extsize; + } + + return NULL; +} + +/* + * A helper function that will load the specified range of cache entries + * from the memory mapped file and add them to the given index. + */ +static unsigned long load_cache_entry_block(struct index_state *istate, + struct mem_pool *ce_mem_pool, int offset, int nr, const char *mmap, + unsigned long start_offset, const struct cache_entry *previous_ce) +{ + int i; + unsigned long src_offset = start_offset; + + for (i = offset; i < offset + nr; i++) { + struct ondisk_cache_entry *disk_ce; + struct cache_entry *ce; + unsigned long consumed; + + disk_ce = (struct ondisk_cache_entry *)(mmap + src_offset); + ce = create_from_disk(ce_mem_pool, istate->version, disk_ce, &consumed, previous_ce); + set_index_entry(istate, i, ce); + + src_offset += consumed; + previous_ce = ce; + } + return src_offset - start_offset; +} + +static unsigned long load_all_cache_entries(struct index_state *istate, + const char *mmap, size_t mmap_size, unsigned long src_offset) +{ + unsigned long consumed; + + if (istate->version == 4) { + mem_pool_init(&istate->ce_mem_pool, + estimate_cache_size_from_compressed(istate->cache_nr)); + } else { + mem_pool_init(&istate->ce_mem_pool, + estimate_cache_size(mmap_size, istate->cache_nr)); + } + + consumed = load_cache_entry_block(istate, istate->ce_mem_pool, + 0, istate->cache_nr, mmap, src_offset, NULL); + return consumed; +} + +/* + * Mostly randomly chosen maximum thread counts: we + * cap the parallelism to online_cpus() threads, and we want + * to have at least 10000 cache entries per thread for it to + * be worth starting a thread. + */ + +#define THREAD_COST (10000) + +struct load_cache_entries_thread_data +{ + pthread_t pthread; + struct index_state *istate; + struct mem_pool *ce_mem_pool; + int offset; + const char *mmap; + struct index_entry_offset_table *ieot; + int ieot_start; /* starting index into the ieot array */ + int ieot_blocks; /* count of ieot entries to process */ + unsigned long consumed; /* return # of bytes in index file processed */ +}; + +/* + * A thread proc to run the load_cache_entries() computation + * across multiple background threads. + */ +static void *load_cache_entries_thread(void *_data) +{ + struct load_cache_entries_thread_data *p = _data; + int i; + + /* iterate across all ieot blocks assigned to this thread */ + for (i = p->ieot_start; i < p->ieot_start + p->ieot_blocks; i++) { + p->consumed += load_cache_entry_block(p->istate, p->ce_mem_pool, + p->offset, p->ieot->entries[i].nr, p->mmap, p->ieot->entries[i].offset, NULL); + p->offset += p->ieot->entries[i].nr; + } + return NULL; +} + +static unsigned long load_cache_entries_threaded(struct index_state *istate, const char *mmap, size_t mmap_size, + int nr_threads, struct index_entry_offset_table *ieot) +{ + int i, offset, ieot_blocks, ieot_start, err; + struct load_cache_entries_thread_data *data; + unsigned long consumed = 0; + + /* a little sanity checking */ + if (istate->name_hash_initialized) + BUG("the name hash isn't thread safe"); + + mem_pool_init(&istate->ce_mem_pool, 0); + + /* ensure we have no more threads than we have blocks to process */ + if (nr_threads > ieot->nr) + nr_threads = ieot->nr; + data = xcalloc(nr_threads, sizeof(*data)); + + offset = ieot_start = 0; + ieot_blocks = DIV_ROUND_UP(ieot->nr, nr_threads); + for (i = 0; i < nr_threads; i++) { + struct load_cache_entries_thread_data *p = &data[i]; + int nr, j; + + if (ieot_start + ieot_blocks > ieot->nr) + ieot_blocks = ieot->nr - ieot_start; + + p->istate = istate; + p->offset = offset; + p->mmap = mmap; + p->ieot = ieot; + p->ieot_start = ieot_start; + p->ieot_blocks = ieot_blocks; + + /* create a mem_pool for each thread */ + nr = 0; + for (j = p->ieot_start; j < p->ieot_start + p->ieot_blocks; j++) + nr += p->ieot->entries[j].nr; + if (istate->version == 4) { + mem_pool_init(&p->ce_mem_pool, + estimate_cache_size_from_compressed(nr)); + } else { + mem_pool_init(&p->ce_mem_pool, + estimate_cache_size(mmap_size, nr)); + } + + err = pthread_create(&p->pthread, NULL, load_cache_entries_thread, p); + if (err) + die(_("unable to create load_cache_entries thread: %s"), strerror(err)); + + /* increment by the number of cache entries in the ieot block being processed */ + for (j = 0; j < ieot_blocks; j++) + offset += ieot->entries[ieot_start + j].nr; + ieot_start += ieot_blocks; + } + + for (i = 0; i < nr_threads; i++) { + struct load_cache_entries_thread_data *p = &data[i]; + + err = pthread_join(p->pthread, NULL); + if (err) + die(_("unable to join load_cache_entries thread: %s"), strerror(err)); + mem_pool_combine(istate->ce_mem_pool, p->ce_mem_pool); + consumed += p->consumed; + } + + free(data); + + return consumed; +} + +/* remember to discard_cache() before reading a different cache! */ +int do_read_index(struct index_state *istate, const char *path, int must_exist) +{ + int fd; + struct stat st; + unsigned long src_offset; + const struct cache_header *hdr; + const char *mmap; + size_t mmap_size; + struct load_index_extensions p; + size_t extension_offset = 0; + int nr_threads, cpus; + struct index_entry_offset_table *ieot = NULL; + + if (istate->initialized) + return istate->cache_nr; + + istate->timestamp.sec = 0; + istate->timestamp.nsec = 0; + fd = open(path, O_RDONLY); + if (fd < 0) { + if (!must_exist && errno == ENOENT) + return 0; + die_errno(_("%s: index file open failed"), path); + } + + if (fstat(fd, &st)) + die_errno(_("%s: cannot stat the open index"), path); + + mmap_size = xsize_t(st.st_size); + if (mmap_size < sizeof(struct cache_header) + the_hash_algo->rawsz) + die(_("%s: index file smaller than expected"), path); + + mmap = xmmap_gently(NULL, mmap_size, PROT_READ, MAP_PRIVATE, fd, 0); + if (mmap == MAP_FAILED) + die_errno(_("%s: unable to map index file"), path); + close(fd); + + hdr = (const struct cache_header *)mmap; + if (verify_hdr(hdr, mmap_size) < 0) + goto unmap; + + hashcpy(istate->oid.hash, (const unsigned char *)hdr + mmap_size - the_hash_algo->rawsz); + istate->version = ntohl(hdr->hdr_version); + istate->cache_nr = ntohl(hdr->hdr_entries); + istate->cache_alloc = alloc_nr(istate->cache_nr); + istate->cache = xcalloc(istate->cache_alloc, sizeof(*istate->cache)); + istate->initialized = 1; + + p.istate = istate; + p.mmap = mmap; + p.mmap_size = mmap_size; + + src_offset = sizeof(*hdr); + + if (git_config_get_index_threads(&nr_threads)) + nr_threads = 1; + + /* TODO: does creating more threads than cores help? */ + if (!nr_threads) { + nr_threads = istate->cache_nr / THREAD_COST; + cpus = online_cpus(); + if (nr_threads > cpus) + nr_threads = cpus; + } + + if (!HAVE_THREADS) + nr_threads = 1; + + if (nr_threads > 1) { + extension_offset = read_eoie_extension(mmap, mmap_size); + if (extension_offset) { + int err; + + p.src_offset = extension_offset; + err = pthread_create(&p.pthread, NULL, load_index_extensions, &p); + if (err) + die(_("unable to create load_index_extensions thread: %s"), strerror(err)); + + nr_threads--; + } + } + + /* + * Locate and read the index entry offset table so that we can use it + * to multi-thread the reading of the cache entries. + */ + if (extension_offset && nr_threads > 1) + ieot = read_ieot_extension(mmap, mmap_size, extension_offset); + + if (ieot) { + src_offset += load_cache_entries_threaded(istate, mmap, mmap_size, nr_threads, ieot); + free(ieot); + } else { + src_offset += load_all_cache_entries(istate, mmap, mmap_size, src_offset); + } + + istate->timestamp.sec = st.st_mtime; + istate->timestamp.nsec = ST_MTIME_NSEC(st); + + /* if we created a thread, join it otherwise load the extensions on the primary thread */ + if (extension_offset) { + int ret = pthread_join(p.pthread, NULL); + if (ret) + die(_("unable to join load_index_extensions thread: %s"), strerror(ret)); + } else { + p.src_offset = src_offset; + load_index_extensions(&p); + } + munmap((void *)mmap, mmap_size); + + /* + * TODO trace2: replace "the_repository" with the actual repo instance + * that is associated with the given "istate". + */ + trace2_data_intmax("index", the_repository, "read/version", + istate->version); + trace2_data_intmax("index", the_repository, "read/cache_nr", + istate->cache_nr); + + return istate->cache_nr; + +unmap: + munmap((void *)mmap, mmap_size); + die(_("index file corrupt")); +} + +/* + * Signal that the shared index is used by updating its mtime. + * + * This way, shared index can be removed if they have not been used + * for some time. + */ +static void freshen_shared_index(const char *shared_index, int warn) +{ + if (!check_and_freshen_file(shared_index, 1) && warn) + warning(_("could not freshen shared index '%s'"), shared_index); +} + +int read_index_from(struct index_state *istate, const char *path, + const char *gitdir) +{ + struct split_index *split_index; + int ret; + char *base_oid_hex; + char *base_path; + + /* istate->initialized covers both .git/index and .git/sharedindex.xxx */ + if (istate->initialized) + return istate->cache_nr; + + /* + * TODO trace2: replace "the_repository" with the actual repo instance + * that is associated with the given "istate". + */ + trace2_region_enter_printf("index", "do_read_index", the_repository, + "%s", path); + trace_performance_enter(); + ret = do_read_index(istate, path, 0); + trace_performance_leave("read cache %s", path); + trace2_region_leave_printf("index", "do_read_index", the_repository, + "%s", path); + + split_index = istate->split_index; + if (!split_index || is_null_oid(&split_index->base_oid)) { + post_read_index_from(istate); + return ret; + } + + trace_performance_enter(); + if (split_index->base) + discard_index(split_index->base); + else + split_index->base = xcalloc(1, sizeof(*split_index->base)); + + base_oid_hex = oid_to_hex(&split_index->base_oid); + base_path = xstrfmt("%s/sharedindex.%s", gitdir, base_oid_hex); + trace2_region_enter_printf("index", "shared/do_read_index", + the_repository, "%s", base_path); + ret = do_read_index(split_index->base, base_path, 1); + trace2_region_leave_printf("index", "shared/do_read_index", + the_repository, "%s", base_path); + if (!oideq(&split_index->base_oid, &split_index->base->oid)) + die(_("broken index, expect %s in %s, got %s"), + base_oid_hex, base_path, + oid_to_hex(&split_index->base->oid)); + + freshen_shared_index(base_path, 0); + merge_base_index(istate); + post_read_index_from(istate); + trace_performance_leave("read cache %s", base_path); + free(base_path); + return ret; +} + +int is_index_unborn(struct index_state *istate) +{ + return (!istate->cache_nr && !istate->timestamp.sec); +} + +int discard_index(struct index_state *istate) +{ + /* + * Cache entries in istate->cache[] should have been allocated + * from the memory pool associated with this index, or from an + * associated split_index. There is no need to free individual + * cache entries. validate_cache_entries can detect when this + * assertion does not hold. + */ + validate_cache_entries(istate); + + resolve_undo_clear_index(istate); + istate->cache_nr = 0; + istate->cache_changed = 0; + istate->timestamp.sec = 0; + istate->timestamp.nsec = 0; + free_name_hash(istate); + cache_tree_free(&(istate->cache_tree)); + istate->initialized = 0; + istate->fsmonitor_has_run_once = 0; + FREE_AND_NULL(istate->cache); + istate->cache_alloc = 0; + discard_split_index(istate); + free_untracked_cache(istate->untracked); + istate->untracked = NULL; + + if (istate->ce_mem_pool) { + mem_pool_discard(istate->ce_mem_pool, should_validate_cache_entries()); + istate->ce_mem_pool = NULL; + } + + return 0; +} + +/* + * Validate the cache entries of this index. + * All cache entries associated with this index + * should have been allocated by the memory pool + * associated with this index, or by a referenced + * split index. + */ +void validate_cache_entries(const struct index_state *istate) +{ + int i; + + if (!should_validate_cache_entries() ||!istate || !istate->initialized) + return; + + for (i = 0; i < istate->cache_nr; i++) { + if (!istate) { + BUG("cache entry is not allocated from expected memory pool"); + } else if (!istate->ce_mem_pool || + !mem_pool_contains(istate->ce_mem_pool, istate->cache[i])) { + if (!istate->split_index || + !istate->split_index->base || + !istate->split_index->base->ce_mem_pool || + !mem_pool_contains(istate->split_index->base->ce_mem_pool, istate->cache[i])) { + BUG("cache entry is not allocated from expected memory pool"); + } + } + } + + if (istate->split_index) + validate_cache_entries(istate->split_index->base); +} + +int unmerged_index(const struct index_state *istate) +{ + int i; + for (i = 0; i < istate->cache_nr; i++) { + if (ce_stage(istate->cache[i])) + return 1; + } + return 0; +} + +int repo_index_has_changes(struct repository *repo, + struct tree *tree, + struct strbuf *sb) +{ + struct index_state *istate = repo->index; + struct object_id cmp; + int i; + + if (tree) + cmp = tree->object.oid; + if (tree || !get_oid_tree("HEAD", &cmp)) { + struct diff_options opt; + + repo_diff_setup(repo, &opt); + opt.flags.exit_with_status = 1; + if (!sb) + opt.flags.quick = 1; + do_diff_cache(&cmp, &opt); + diffcore_std(&opt); + for (i = 0; sb && i < diff_queued_diff.nr; i++) { + if (i) + strbuf_addch(sb, ' '); + strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path); + } + diff_flush(&opt); + return opt.flags.has_changes != 0; + } else { + for (i = 0; sb && i < istate->cache_nr; i++) { + if (i) + strbuf_addch(sb, ' '); + strbuf_addstr(sb, istate->cache[i]->name); + } + return !!istate->cache_nr; + } +} + +#define WRITE_BUFFER_SIZE 8192 +static unsigned char write_buffer[WRITE_BUFFER_SIZE]; +static unsigned long write_buffer_len; + +static int ce_write_flush(git_hash_ctx *context, int fd) +{ + unsigned int buffered = write_buffer_len; + if (buffered) { + the_hash_algo->update_fn(context, write_buffer, buffered); + if (write_in_full(fd, write_buffer, buffered) < 0) + return -1; + write_buffer_len = 0; + } + return 0; +} + +static int ce_write(git_hash_ctx *context, int fd, void *data, unsigned int len) +{ + while (len) { + unsigned int buffered = write_buffer_len; + unsigned int partial = WRITE_BUFFER_SIZE - buffered; + if (partial > len) + partial = len; + memcpy(write_buffer + buffered, data, partial); + buffered += partial; + if (buffered == WRITE_BUFFER_SIZE) { + write_buffer_len = buffered; + if (ce_write_flush(context, fd)) + return -1; + buffered = 0; + } + write_buffer_len = buffered; + len -= partial; + data = (char *) data + partial; + } + return 0; +} + +static int write_index_ext_header(git_hash_ctx *context, git_hash_ctx *eoie_context, + int fd, unsigned int ext, unsigned int sz) +{ + ext = htonl(ext); + sz = htonl(sz); + if (eoie_context) { + the_hash_algo->update_fn(eoie_context, &ext, 4); + the_hash_algo->update_fn(eoie_context, &sz, 4); + } + return ((ce_write(context, fd, &ext, 4) < 0) || + (ce_write(context, fd, &sz, 4) < 0)) ? -1 : 0; +} + +static int ce_flush(git_hash_ctx *context, int fd, unsigned char *hash) +{ + unsigned int left = write_buffer_len; + + if (left) { + write_buffer_len = 0; + the_hash_algo->update_fn(context, write_buffer, left); + } + + /* Flush first if not enough space for hash signature */ + if (left + the_hash_algo->rawsz > WRITE_BUFFER_SIZE) { + if (write_in_full(fd, write_buffer, left) < 0) + return -1; + left = 0; + } + + /* Append the hash signature at the end */ + the_hash_algo->final_fn(write_buffer + left, context); + hashcpy(hash, write_buffer + left); + left += the_hash_algo->rawsz; + return (write_in_full(fd, write_buffer, left) < 0) ? -1 : 0; +} + +static void ce_smudge_racily_clean_entry(struct index_state *istate, + struct cache_entry *ce) +{ + /* + * The only thing we care about in this function is to smudge the + * falsely clean entry due to touch-update-touch race, so we leave + * everything else as they are. We are called for entries whose + * ce_stat_data.sd_mtime match the index file mtime. + * + * Note that this actually does not do much for gitlinks, for + * which ce_match_stat_basic() always goes to the actual + * contents. The caller checks with is_racy_timestamp() which + * always says "no" for gitlinks, so we are not called for them ;-) + */ + struct stat st; + + if (lstat(ce->name, &st) < 0) + return; + if (ce_match_stat_basic(ce, &st)) + return; + if (ce_modified_check_fs(istate, ce, &st)) { + /* This is "racily clean"; smudge it. Note that this + * is a tricky code. At first glance, it may appear + * that it can break with this sequence: + * + * $ echo xyzzy >frotz + * $ git-update-index --add frotz + * $ : >frotz + * $ sleep 3 + * $ echo filfre >nitfol + * $ git-update-index --add nitfol + * + * but it does not. When the second update-index runs, + * it notices that the entry "frotz" has the same timestamp + * as index, and if we were to smudge it by resetting its + * size to zero here, then the object name recorded + * in index is the 6-byte file but the cached stat information + * becomes zero --- which would then match what we would + * obtain from the filesystem next time we stat("frotz"). + * + * However, the second update-index, before calling + * this function, notices that the cached size is 6 + * bytes and what is on the filesystem is an empty + * file, and never calls us, so the cached size information + * for "frotz" stays 6 which does not match the filesystem. + */ + ce->ce_stat_data.sd_size = 0; + } +} + +/* Copy miscellaneous fields but not the name */ +static void copy_cache_entry_to_ondisk(struct ondisk_cache_entry *ondisk, + struct cache_entry *ce) +{ + short flags; + const unsigned hashsz = the_hash_algo->rawsz; + uint16_t *flagsp = (uint16_t *)(ondisk->data + hashsz); + + ondisk->ctime.sec = htonl(ce->ce_stat_data.sd_ctime.sec); + ondisk->mtime.sec = htonl(ce->ce_stat_data.sd_mtime.sec); + ondisk->ctime.nsec = htonl(ce->ce_stat_data.sd_ctime.nsec); + ondisk->mtime.nsec = htonl(ce->ce_stat_data.sd_mtime.nsec); + ondisk->dev = htonl(ce->ce_stat_data.sd_dev); + ondisk->ino = htonl(ce->ce_stat_data.sd_ino); + ondisk->mode = htonl(ce->ce_mode); + ondisk->uid = htonl(ce->ce_stat_data.sd_uid); + ondisk->gid = htonl(ce->ce_stat_data.sd_gid); + ondisk->size = htonl(ce->ce_stat_data.sd_size); + hashcpy(ondisk->data, ce->oid.hash); + + flags = ce->ce_flags & ~CE_NAMEMASK; + flags |= (ce_namelen(ce) >= CE_NAMEMASK ? CE_NAMEMASK : ce_namelen(ce)); + flagsp[0] = htons(flags); + if (ce->ce_flags & CE_EXTENDED) { + flagsp[1] = htons((ce->ce_flags & CE_EXTENDED_FLAGS) >> 16); + } +} + +static int ce_write_entry(git_hash_ctx *c, int fd, struct cache_entry *ce, + struct strbuf *previous_name, struct ondisk_cache_entry *ondisk) +{ + int size; + int result; + unsigned int saved_namelen; + int stripped_name = 0; + static unsigned char padding[8] = { 0x00 }; + + if (ce->ce_flags & CE_STRIP_NAME) { + saved_namelen = ce_namelen(ce); + ce->ce_namelen = 0; + stripped_name = 1; + } + + size = offsetof(struct ondisk_cache_entry,data) + ondisk_data_size(ce->ce_flags, 0); + + if (!previous_name) { + int len = ce_namelen(ce); + copy_cache_entry_to_ondisk(ondisk, ce); + result = ce_write(c, fd, ondisk, size); + if (!result) + result = ce_write(c, fd, ce->name, len); + if (!result) + result = ce_write(c, fd, padding, align_padding_size(size, len)); + } else { + int common, to_remove, prefix_size; + unsigned char to_remove_vi[16]; + for (common = 0; + (ce->name[common] && + common < previous_name->len && + ce->name[common] == previous_name->buf[common]); + common++) + ; /* still matching */ + to_remove = previous_name->len - common; + prefix_size = encode_varint(to_remove, to_remove_vi); + + copy_cache_entry_to_ondisk(ondisk, ce); + result = ce_write(c, fd, ondisk, size); + if (!result) + result = ce_write(c, fd, to_remove_vi, prefix_size); + if (!result) + result = ce_write(c, fd, ce->name + common, ce_namelen(ce) - common); + if (!result) + result = ce_write(c, fd, padding, 1); + + strbuf_splice(previous_name, common, to_remove, + ce->name + common, ce_namelen(ce) - common); + } + if (stripped_name) { + ce->ce_namelen = saved_namelen; + ce->ce_flags &= ~CE_STRIP_NAME; + } + + return result; +} + +/* + * This function verifies if index_state has the correct sha1 of the + * index file. Don't die if we have any other failure, just return 0. + */ +static int verify_index_from(const struct index_state *istate, const char *path) +{ + int fd; + ssize_t n; + struct stat st; + unsigned char hash[GIT_MAX_RAWSZ]; + + if (!istate->initialized) + return 0; + + fd = open(path, O_RDONLY); + if (fd < 0) + return 0; + + if (fstat(fd, &st)) + goto out; + + if (st.st_size < sizeof(struct cache_header) + the_hash_algo->rawsz) + goto out; + + n = pread_in_full(fd, hash, the_hash_algo->rawsz, st.st_size - the_hash_algo->rawsz); + if (n != the_hash_algo->rawsz) + goto out; + + if (!hasheq(istate->oid.hash, hash)) + goto out; + + close(fd); + return 1; + +out: + close(fd); + return 0; +} + +static int repo_verify_index(struct repository *repo) +{ + return verify_index_from(repo->index, repo->index_file); +} + +static int has_racy_timestamp(struct index_state *istate) +{ + int entries = istate->cache_nr; + int i; + + for (i = 0; i < entries; i++) { + struct cache_entry *ce = istate->cache[i]; + if (is_racy_timestamp(istate, ce)) + return 1; + } + return 0; +} + +void repo_update_index_if_able(struct repository *repo, + struct lock_file *lockfile) +{ + if ((repo->index->cache_changed || + has_racy_timestamp(repo->index)) && + repo_verify_index(repo)) + write_locked_index(repo->index, lockfile, COMMIT_LOCK); + else + rollback_lock_file(lockfile); +} + +static int record_eoie(void) +{ + int val; + + if (!git_config_get_bool("index.recordendofindexentries", &val)) + return val; + + /* + * As a convenience, the end of index entries extension + * used for threading is written by default if the user + * explicitly requested threaded index reads. + */ + return !git_config_get_index_threads(&val) && val != 1; +} + +static int record_ieot(void) +{ + int val; + + if (!git_config_get_bool("index.recordoffsettable", &val)) + return val; + + /* + * As a convenience, the offset table used for threading is + * written by default if the user explicitly requested + * threaded index reads. + */ + return !git_config_get_index_threads(&val) && val != 1; +} + +/* + * On success, `tempfile` is closed. If it is the temporary file + * of a `struct lock_file`, we will therefore effectively perform + * a 'close_lock_file_gently()`. Since that is an implementation + * detail of lockfiles, callers of `do_write_index()` should not + * rely on it. + */ +static int do_write_index(struct index_state *istate, struct tempfile *tempfile, + int strip_extensions) +{ + uint64_t start = getnanotime(); + int newfd = tempfile->fd; + git_hash_ctx c, eoie_c; + struct cache_header hdr; + int i, err = 0, removed, extended, hdr_version; + struct cache_entry **cache = istate->cache; + int entries = istate->cache_nr; + struct stat st; + struct ondisk_cache_entry ondisk; + struct strbuf previous_name_buf = STRBUF_INIT, *previous_name; + int drop_cache_tree = istate->drop_cache_tree; + off_t offset; + int ieot_entries = 1; + struct index_entry_offset_table *ieot = NULL; + int nr, nr_threads; + + for (i = removed = extended = 0; i < entries; i++) { + if (cache[i]->ce_flags & CE_REMOVE) + removed++; + + /* reduce extended entries if possible */ + cache[i]->ce_flags &= ~CE_EXTENDED; + if (cache[i]->ce_flags & CE_EXTENDED_FLAGS) { + extended++; + cache[i]->ce_flags |= CE_EXTENDED; + } + } + + if (!istate->version) { + istate->version = get_index_format_default(); + if (git_env_bool("GIT_TEST_SPLIT_INDEX", 0)) + init_split_index(istate); + } + + /* demote version 3 to version 2 when the latter suffices */ + if (istate->version == 3 || istate->version == 2) + istate->version = extended ? 3 : 2; + + hdr_version = istate->version; + + hdr.hdr_signature = htonl(CACHE_SIGNATURE); + hdr.hdr_version = htonl(hdr_version); + hdr.hdr_entries = htonl(entries - removed); + + the_hash_algo->init_fn(&c); + if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0) + return -1; + + if (!HAVE_THREADS || git_config_get_index_threads(&nr_threads)) + nr_threads = 1; + + if (nr_threads != 1 && record_ieot()) { + int ieot_blocks, cpus; + + /* + * ensure default number of ieot blocks maps evenly to the + * default number of threads that will process them leaving + * room for the thread to load the index extensions. + */ + if (!nr_threads) { + ieot_blocks = istate->cache_nr / THREAD_COST; + cpus = online_cpus(); + if (ieot_blocks > cpus - 1) + ieot_blocks = cpus - 1; + } else { + ieot_blocks = nr_threads; + if (ieot_blocks > istate->cache_nr) + ieot_blocks = istate->cache_nr; + } + + /* + * no reason to write out the IEOT extension if we don't + * have enough blocks to utilize multi-threading + */ + if (ieot_blocks > 1) { + ieot = xcalloc(1, sizeof(struct index_entry_offset_table) + + (ieot_blocks * sizeof(struct index_entry_offset))); + ieot_entries = DIV_ROUND_UP(entries, ieot_blocks); + } + } + + offset = lseek(newfd, 0, SEEK_CUR); + if (offset < 0) { + free(ieot); + return -1; + } + offset += write_buffer_len; + nr = 0; + previous_name = (hdr_version == 4) ? &previous_name_buf : NULL; + + for (i = 0; i < entries; i++) { + struct cache_entry *ce = cache[i]; + if (ce->ce_flags & CE_REMOVE) + continue; + if (!ce_uptodate(ce) && is_racy_timestamp(istate, ce)) + ce_smudge_racily_clean_entry(istate, ce); + if (is_null_oid(&ce->oid)) { + static const char msg[] = "cache entry has null sha1: %s"; + static int allow = -1; + + if (allow < 0) + allow = git_env_bool("GIT_ALLOW_NULL_SHA1", 0); + if (allow) + warning(msg, ce->name); + else + err = error(msg, ce->name); + + drop_cache_tree = 1; + } + if (ieot && i && (i % ieot_entries == 0)) { + ieot->entries[ieot->nr].nr = nr; + ieot->entries[ieot->nr].offset = offset; + ieot->nr++; + /* + * If we have a V4 index, set the first byte to an invalid + * character to ensure there is nothing common with the previous + * entry + */ + if (previous_name) + previous_name->buf[0] = 0; + nr = 0; + offset = lseek(newfd, 0, SEEK_CUR); + if (offset < 0) { + free(ieot); + return -1; + } + offset += write_buffer_len; + } + if (ce_write_entry(&c, newfd, ce, previous_name, (struct ondisk_cache_entry *)&ondisk) < 0) + err = -1; + + if (err) + break; + nr++; + } + if (ieot && nr) { + ieot->entries[ieot->nr].nr = nr; + ieot->entries[ieot->nr].offset = offset; + ieot->nr++; + } + strbuf_release(&previous_name_buf); + + if (err) { + free(ieot); + return err; + } + + /* Write extension data here */ + offset = lseek(newfd, 0, SEEK_CUR); + if (offset < 0) { + free(ieot); + return -1; + } + offset += write_buffer_len; + the_hash_algo->init_fn(&eoie_c); + + /* + * Lets write out CACHE_EXT_INDEXENTRYOFFSETTABLE first so that we + * can minimize the number of extensions we have to scan through to + * find it during load. Write it out regardless of the + * strip_extensions parameter as we need it when loading the shared + * index. + */ + if (ieot) { + struct strbuf sb = STRBUF_INIT; + + write_ieot_extension(&sb, ieot); + err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_INDEXENTRYOFFSETTABLE, sb.len) < 0 + || ce_write(&c, newfd, sb.buf, sb.len) < 0; + strbuf_release(&sb); + free(ieot); + if (err) + return -1; + } + + if (!strip_extensions && istate->split_index && + !is_null_oid(&istate->split_index->base_oid)) { + struct strbuf sb = STRBUF_INIT; + + err = write_link_extension(&sb, istate) < 0 || + write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_LINK, + sb.len) < 0 || + ce_write(&c, newfd, sb.buf, sb.len) < 0; + strbuf_release(&sb); + if (err) + return -1; + } + if (!strip_extensions && !drop_cache_tree && istate->cache_tree) { + struct strbuf sb = STRBUF_INIT; + + cache_tree_write(&sb, istate->cache_tree); + err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_TREE, sb.len) < 0 + || ce_write(&c, newfd, sb.buf, sb.len) < 0; + strbuf_release(&sb); + if (err) + return -1; + } + if (!strip_extensions && istate->resolve_undo) { + struct strbuf sb = STRBUF_INIT; + + resolve_undo_write(&sb, istate->resolve_undo); + err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_RESOLVE_UNDO, + sb.len) < 0 + || ce_write(&c, newfd, sb.buf, sb.len) < 0; + strbuf_release(&sb); + if (err) + return -1; + } + if (!strip_extensions && istate->untracked) { + struct strbuf sb = STRBUF_INIT; + + write_untracked_extension(&sb, istate->untracked); + err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_UNTRACKED, + sb.len) < 0 || + ce_write(&c, newfd, sb.buf, sb.len) < 0; + strbuf_release(&sb); + if (err) + return -1; + } + if (!strip_extensions && istate->fsmonitor_last_update) { + struct strbuf sb = STRBUF_INIT; + + write_fsmonitor_extension(&sb, istate); + err = write_index_ext_header(&c, &eoie_c, newfd, CACHE_EXT_FSMONITOR, sb.len) < 0 + || ce_write(&c, newfd, sb.buf, sb.len) < 0; + strbuf_release(&sb); + if (err) + return -1; + } + + /* + * CACHE_EXT_ENDOFINDEXENTRIES must be written as the last entry before the SHA1 + * so that it can be found and processed before all the index entries are + * read. Write it out regardless of the strip_extensions parameter as we need it + * when loading the shared index. + */ + if (offset && record_eoie()) { + struct strbuf sb = STRBUF_INIT; + + write_eoie_extension(&sb, &eoie_c, offset); + err = write_index_ext_header(&c, NULL, newfd, CACHE_EXT_ENDOFINDEXENTRIES, sb.len) < 0 + || ce_write(&c, newfd, sb.buf, sb.len) < 0; + strbuf_release(&sb); + if (err) + return -1; + } + + if (ce_flush(&c, newfd, istate->oid.hash)) + return -1; + if (close_tempfile_gently(tempfile)) { + error(_("could not close '%s'"), tempfile->filename.buf); + return -1; + } + if (stat(tempfile->filename.buf, &st)) + return -1; + istate->timestamp.sec = (unsigned int)st.st_mtime; + istate->timestamp.nsec = ST_MTIME_NSEC(st); + trace_performance_since(start, "write index, changed mask = %x", istate->cache_changed); + + /* + * TODO trace2: replace "the_repository" with the actual repo instance + * that is associated with the given "istate". + */ + trace2_data_intmax("index", the_repository, "write/version", + istate->version); + trace2_data_intmax("index", the_repository, "write/cache_nr", + istate->cache_nr); + + return 0; +} + +void set_alternate_index_output(const char *name) +{ + alternate_index_output = name; +} + +static int commit_locked_index(struct lock_file *lk) +{ + if (alternate_index_output) + return commit_lock_file_to(lk, alternate_index_output); + else + return commit_lock_file(lk); +} + +static int do_write_locked_index(struct index_state *istate, struct lock_file *lock, + unsigned flags) +{ + int ret; + + /* + * TODO trace2: replace "the_repository" with the actual repo instance + * that is associated with the given "istate". + */ + trace2_region_enter_printf("index", "do_write_index", the_repository, + "%s", lock->tempfile->filename.buf); + ret = do_write_index(istate, lock->tempfile, 0); + trace2_region_leave_printf("index", "do_write_index", the_repository, + "%s", lock->tempfile->filename.buf); + + if (ret) + return ret; + if (flags & COMMIT_LOCK) + ret = commit_locked_index(lock); + else + ret = close_lock_file_gently(lock); + + run_hook_le(NULL, "post-index-change", + istate->updated_workdir ? "1" : "0", + istate->updated_skipworktree ? "1" : "0", NULL); + istate->updated_workdir = 0; + istate->updated_skipworktree = 0; + + return ret; +} + +static int write_split_index(struct index_state *istate, + struct lock_file *lock, + unsigned flags) +{ + int ret; + prepare_to_write_split_index(istate); + ret = do_write_locked_index(istate, lock, flags); + finish_writing_split_index(istate); + return ret; +} + +static const char *shared_index_expire = "2.weeks.ago"; + +static unsigned long get_shared_index_expire_date(void) +{ + static unsigned long shared_index_expire_date; + static int shared_index_expire_date_prepared; + + if (!shared_index_expire_date_prepared) { + git_config_get_expiry("splitindex.sharedindexexpire", + &shared_index_expire); + shared_index_expire_date = approxidate(shared_index_expire); + shared_index_expire_date_prepared = 1; + } + + return shared_index_expire_date; +} + +static int should_delete_shared_index(const char *shared_index_path) +{ + struct stat st; + unsigned long expiration; + + /* Check timestamp */ + expiration = get_shared_index_expire_date(); + if (!expiration) + return 0; + if (stat(shared_index_path, &st)) + return error_errno(_("could not stat '%s'"), shared_index_path); + if (st.st_mtime > expiration) + return 0; + + return 1; +} + +static int clean_shared_index_files(const char *current_hex) +{ + struct dirent *de; + DIR *dir = opendir(get_git_dir()); + + if (!dir) + return error_errno(_("unable to open git dir: %s"), get_git_dir()); + + while ((de = readdir(dir)) != NULL) { + const char *sha1_hex; + const char *shared_index_path; + if (!skip_prefix(de->d_name, "sharedindex.", &sha1_hex)) + continue; + if (!strcmp(sha1_hex, current_hex)) + continue; + shared_index_path = git_path("%s", de->d_name); + if (should_delete_shared_index(shared_index_path) > 0 && + unlink(shared_index_path)) + warning_errno(_("unable to unlink: %s"), shared_index_path); + } + closedir(dir); + + return 0; +} + +static int write_shared_index(struct index_state *istate, + struct tempfile **temp) +{ + struct split_index *si = istate->split_index; + int ret; + + move_cache_to_base_index(istate); + + trace2_region_enter_printf("index", "shared/do_write_index", + the_repository, "%s", (*temp)->filename.buf); + ret = do_write_index(si->base, *temp, 1); + trace2_region_leave_printf("index", "shared/do_write_index", + the_repository, "%s", (*temp)->filename.buf); + + if (ret) + return ret; + ret = adjust_shared_perm(get_tempfile_path(*temp)); + if (ret) { + error(_("cannot fix permission bits on '%s'"), get_tempfile_path(*temp)); + return ret; + } + ret = rename_tempfile(temp, + git_path("sharedindex.%s", oid_to_hex(&si->base->oid))); + if (!ret) { + oidcpy(&si->base_oid, &si->base->oid); + clean_shared_index_files(oid_to_hex(&si->base->oid)); + } + + return ret; +} + +static const int default_max_percent_split_change = 20; + +static int too_many_not_shared_entries(struct index_state *istate) +{ + int i, not_shared = 0; + int max_split = git_config_get_max_percent_split_change(); + + switch (max_split) { + case -1: + /* not or badly configured: use the default value */ + max_split = default_max_percent_split_change; + break; + case 0: + return 1; /* 0% means always write a new shared index */ + case 100: + return 0; /* 100% means never write a new shared index */ + default: + break; /* just use the configured value */ + } + + /* Count not shared entries */ + for (i = 0; i < istate->cache_nr; i++) { + struct cache_entry *ce = istate->cache[i]; + if (!ce->index) + not_shared++; + } + + return (int64_t)istate->cache_nr * max_split < (int64_t)not_shared * 100; +} + +int write_locked_index(struct index_state *istate, struct lock_file *lock, + unsigned flags) +{ + int new_shared_index, ret; + struct split_index *si = istate->split_index; + + if (git_env_bool("GIT_TEST_CHECK_CACHE_TREE", 0)) + cache_tree_verify(the_repository, istate); + + if ((flags & SKIP_IF_UNCHANGED) && !istate->cache_changed) { + if (flags & COMMIT_LOCK) + rollback_lock_file(lock); + return 0; + } + + if (istate->fsmonitor_last_update) + fill_fsmonitor_bitmap(istate); + + if (!si || alternate_index_output || + (istate->cache_changed & ~EXTMASK)) { + if (si) + oidclr(&si->base_oid); + ret = do_write_locked_index(istate, lock, flags); + goto out; + } + + if (git_env_bool("GIT_TEST_SPLIT_INDEX", 0)) { + int v = si->base_oid.hash[0]; + if ((v & 15) < 6) + istate->cache_changed |= SPLIT_INDEX_ORDERED; + } + if (too_many_not_shared_entries(istate)) + istate->cache_changed |= SPLIT_INDEX_ORDERED; + + new_shared_index = istate->cache_changed & SPLIT_INDEX_ORDERED; + + if (new_shared_index) { + struct tempfile *temp; + int saved_errno; + + /* Same initial permissions as the main .git/index file */ + temp = mks_tempfile_sm(git_path("sharedindex_XXXXXX"), 0, 0666); + if (!temp) { + oidclr(&si->base_oid); + ret = do_write_locked_index(istate, lock, flags); + goto out; + } + ret = write_shared_index(istate, &temp); + + saved_errno = errno; + if (is_tempfile_active(temp)) + delete_tempfile(&temp); + errno = saved_errno; + + if (ret) + goto out; + } + + ret = write_split_index(istate, lock, flags); + + /* Freshen the shared index only if the split-index was written */ + if (!ret && !new_shared_index && !is_null_oid(&si->base_oid)) { + const char *shared_index = git_path("sharedindex.%s", + oid_to_hex(&si->base_oid)); + freshen_shared_index(shared_index, 1); + } + +out: + if (flags & COMMIT_LOCK) + rollback_lock_file(lock); + return ret; +} + +/* + * Read the index file that is potentially unmerged into given + * index_state, dropping any unmerged entries to stage #0 (potentially + * resulting in a path appearing as both a file and a directory in the + * index; the caller is responsible to clear out the extra entries + * before writing the index to a tree). Returns true if the index is + * unmerged. Callers who want to refuse to work from an unmerged + * state can call this and check its return value, instead of calling + * read_cache(). + */ +int repo_read_index_unmerged(struct repository *repo) +{ + struct index_state *istate; + int i; + int unmerged = 0; + + repo_read_index(repo); + istate = repo->index; + for (i = 0; i < istate->cache_nr; i++) { + struct cache_entry *ce = istate->cache[i]; + struct cache_entry *new_ce; + int len; + + if (!ce_stage(ce)) + continue; + unmerged = 1; + len = ce_namelen(ce); + new_ce = make_empty_cache_entry(istate, len); + memcpy(new_ce->name, ce->name, len); + new_ce->ce_flags = create_ce_flags(0) | CE_CONFLICTED; + new_ce->ce_namelen = len; + new_ce->ce_mode = ce->ce_mode; + if (add_index_entry(istate, new_ce, ADD_CACHE_SKIP_DFCHECK)) + return error(_("%s: cannot drop to stage #0"), + new_ce->name); + } + return unmerged; +} + +/* + * Returns 1 if the path is an "other" path with respect to + * the index; that is, the path is not mentioned in the index at all, + * either as a file, a directory with some files in the index, + * or as an unmerged entry. + * + * We helpfully remove a trailing "/" from directories so that + * the output of read_directory can be used as-is. + */ +int index_name_is_other(const struct index_state *istate, const char *name, + int namelen) +{ + int pos; + if (namelen && name[namelen - 1] == '/') + namelen--; + pos = index_name_pos(istate, name, namelen); + if (0 <= pos) + return 0; /* exact match */ + pos = -pos - 1; + if (pos < istate->cache_nr) { + struct cache_entry *ce = istate->cache[pos]; + if (ce_namelen(ce) == namelen && + !memcmp(ce->name, name, namelen)) + return 0; /* Yup, this one exists unmerged */ + } + return 1; +} + +void *read_blob_data_from_index(const struct index_state *istate, + const char *path, unsigned long *size) +{ + int pos, len; + unsigned long sz; + enum object_type type; + void *data; + + len = strlen(path); + pos = index_name_pos(istate, path, len); + if (pos < 0) { + /* + * We might be in the middle of a merge, in which + * case we would read stage #2 (ours). + */ + int i; + for (i = -pos - 1; + (pos < 0 && i < istate->cache_nr && + !strcmp(istate->cache[i]->name, path)); + i++) + if (ce_stage(istate->cache[i]) == 2) + pos = i; + } + if (pos < 0) + return NULL; + data = read_object_file(&istate->cache[pos]->oid, &type, &sz); + if (!data || type != OBJ_BLOB) { + free(data); + return NULL; + } + if (size) + *size = sz; + return data; +} + +void stat_validity_clear(struct stat_validity *sv) +{ + FREE_AND_NULL(sv->sd); +} + +int stat_validity_check(struct stat_validity *sv, const char *path) +{ + struct stat st; + + if (stat(path, &st) < 0) + return sv->sd == NULL; + if (!sv->sd) + return 0; + return S_ISREG(st.st_mode) && !match_stat_data(sv->sd, &st); +} + +void stat_validity_update(struct stat_validity *sv, int fd) +{ + struct stat st; + + if (fstat(fd, &st) < 0 || !S_ISREG(st.st_mode)) + stat_validity_clear(sv); + else { + if (!sv->sd) + sv->sd = xcalloc(1, sizeof(struct stat_data)); + fill_stat_data(sv->sd, &st); + } +} + +void move_index_extensions(struct index_state *dst, struct index_state *src) +{ + dst->untracked = src->untracked; + src->untracked = NULL; + dst->cache_tree = src->cache_tree; + src->cache_tree = NULL; +} + +struct cache_entry *dup_cache_entry(const struct cache_entry *ce, + struct index_state *istate) +{ + unsigned int size = ce_size(ce); + int mem_pool_allocated; + struct cache_entry *new_entry = make_empty_cache_entry(istate, ce_namelen(ce)); + mem_pool_allocated = new_entry->mem_pool_allocated; + + memcpy(new_entry, ce, size); + new_entry->mem_pool_allocated = mem_pool_allocated; + return new_entry; +} + +void discard_cache_entry(struct cache_entry *ce) +{ + if (ce && should_validate_cache_entries()) + memset(ce, 0xCD, cache_entry_size(ce->ce_namelen)); + + if (ce && ce->mem_pool_allocated) + return; + + free(ce); +} + +int should_validate_cache_entries(void) +{ + static int validate_index_cache_entries = -1; + + if (validate_index_cache_entries < 0) { + if (getenv("GIT_TEST_VALIDATE_INDEX_CACHE_ENTRIES")) + validate_index_cache_entries = 1; + else + validate_index_cache_entries = 0; + } + + return validate_index_cache_entries; +} + +#define EOIE_SIZE (4 + GIT_SHA1_RAWSZ) /* <4-byte offset> + <20-byte hash> */ +#define EOIE_SIZE_WITH_HEADER (4 + 4 + EOIE_SIZE) /* <4-byte signature> + <4-byte length> + EOIE_SIZE */ + +static size_t read_eoie_extension(const char *mmap, size_t mmap_size) +{ + /* + * The end of index entries (EOIE) extension is guaranteed to be last + * so that it can be found by scanning backwards from the EOF. + * + * "EOIE" + * <4-byte length> + * <4-byte offset> + * <20-byte hash> + */ + const char *index, *eoie; + uint32_t extsize; + size_t offset, src_offset; + unsigned char hash[GIT_MAX_RAWSZ]; + git_hash_ctx c; + + /* ensure we have an index big enough to contain an EOIE extension */ + if (mmap_size < sizeof(struct cache_header) + EOIE_SIZE_WITH_HEADER + the_hash_algo->rawsz) + return 0; + + /* validate the extension signature */ + index = eoie = mmap + mmap_size - EOIE_SIZE_WITH_HEADER - the_hash_algo->rawsz; + if (CACHE_EXT(index) != CACHE_EXT_ENDOFINDEXENTRIES) + return 0; + index += sizeof(uint32_t); + + /* validate the extension size */ + extsize = get_be32(index); + if (extsize != EOIE_SIZE) + return 0; + index += sizeof(uint32_t); + + /* + * Validate the offset we're going to look for the first extension + * signature is after the index header and before the eoie extension. + */ + offset = get_be32(index); + if (mmap + offset < mmap + sizeof(struct cache_header)) + return 0; + if (mmap + offset >= eoie) + return 0; + index += sizeof(uint32_t); + + /* + * The hash is computed over extension types and their sizes (but not + * their contents). E.g. if we have "TREE" extension that is N-bytes + * long, "REUC" extension that is M-bytes long, followed by "EOIE", + * then the hash would be: + * + * SHA-1("TREE" + <binary representation of N> + + * "REUC" + <binary representation of M>) + */ + src_offset = offset; + the_hash_algo->init_fn(&c); + while (src_offset < mmap_size - the_hash_algo->rawsz - EOIE_SIZE_WITH_HEADER) { + /* After an array of active_nr index entries, + * there can be arbitrary number of extended + * sections, each of which is prefixed with + * extension name (4-byte) and section length + * in 4-byte network byte order. + */ + uint32_t extsize; + memcpy(&extsize, mmap + src_offset + 4, 4); + extsize = ntohl(extsize); + + /* verify the extension size isn't so large it will wrap around */ + if (src_offset + 8 + extsize < src_offset) + return 0; + + the_hash_algo->update_fn(&c, mmap + src_offset, 8); + + src_offset += 8; + src_offset += extsize; + } + the_hash_algo->final_fn(hash, &c); + if (!hasheq(hash, (const unsigned char *)index)) + return 0; + + /* Validate that the extension offsets returned us back to the eoie extension. */ + if (src_offset != mmap_size - the_hash_algo->rawsz - EOIE_SIZE_WITH_HEADER) + return 0; + + return offset; +} + +static void write_eoie_extension(struct strbuf *sb, git_hash_ctx *eoie_context, size_t offset) +{ + uint32_t buffer; + unsigned char hash[GIT_MAX_RAWSZ]; + + /* offset */ + put_be32(&buffer, offset); + strbuf_add(sb, &buffer, sizeof(uint32_t)); + + /* hash */ + the_hash_algo->final_fn(hash, eoie_context); + strbuf_add(sb, hash, the_hash_algo->rawsz); +} + +#define IEOT_VERSION (1) + +static struct index_entry_offset_table *read_ieot_extension(const char *mmap, size_t mmap_size, size_t offset) +{ + const char *index = NULL; + uint32_t extsize, ext_version; + struct index_entry_offset_table *ieot; + int i, nr; + + /* find the IEOT extension */ + if (!offset) + return NULL; + while (offset <= mmap_size - the_hash_algo->rawsz - 8) { + extsize = get_be32(mmap + offset + 4); + if (CACHE_EXT((mmap + offset)) == CACHE_EXT_INDEXENTRYOFFSETTABLE) { + index = mmap + offset + 4 + 4; + break; + } + offset += 8; + offset += extsize; + } + if (!index) + return NULL; + + /* validate the version is IEOT_VERSION */ + ext_version = get_be32(index); + if (ext_version != IEOT_VERSION) { + error("invalid IEOT version %d", ext_version); + return NULL; + } + index += sizeof(uint32_t); + + /* extension size - version bytes / bytes per entry */ + nr = (extsize - sizeof(uint32_t)) / (sizeof(uint32_t) + sizeof(uint32_t)); + if (!nr) { + error("invalid number of IEOT entries %d", nr); + return NULL; + } + ieot = xmalloc(sizeof(struct index_entry_offset_table) + + (nr * sizeof(struct index_entry_offset))); + ieot->nr = nr; + for (i = 0; i < nr; i++) { + ieot->entries[i].offset = get_be32(index); + index += sizeof(uint32_t); + ieot->entries[i].nr = get_be32(index); + index += sizeof(uint32_t); + } + + return ieot; +} + +static void write_ieot_extension(struct strbuf *sb, struct index_entry_offset_table *ieot) +{ + uint32_t buffer; + int i; + + /* version */ + put_be32(&buffer, IEOT_VERSION); + strbuf_add(sb, &buffer, sizeof(uint32_t)); + + /* ieot */ + for (i = 0; i < ieot->nr; i++) { + + /* offset */ + put_be32(&buffer, ieot->entries[i].offset); + strbuf_add(sb, &buffer, sizeof(uint32_t)); + + /* count */ + put_be32(&buffer, ieot->entries[i].nr); + strbuf_add(sb, &buffer, sizeof(uint32_t)); + } +} |